Turbine blade spraying clamping fixture and spraying method

Abstract

This invention discloses a turbine blade spraying clamping fixture, relating to the field of turbine blade thermal barrier coating preparation technology. It includes a lower connecting rod, a lower frame, and an upper frame coaxially assembled sequentially, as well as an adjustable support assembly, a radial positioning assembly, and a counterweight balancing assembly. Currently, the tooling and processes used in turbine blade thermal spraying preparation have significant technical deficiencies, failing to meet the mass production requirements of high-end equipment. This invention achieves high-precision clamping of turbine blades and full-process controllable coating quality through modular tooling design and a zoned closed-loop spraying process.

Description

Technical Field

[0001] This invention relates to the field of turbine blade thermal barrier coating preparation technology, specifically to turbine blade spraying clamping fixture and spraying method. Background Technology

[0002] As heavy-duty gas turbines and aero engines develop towards higher thrust-to-weight ratios and higher turbine inlet temperatures, the uniformity, adhesion, batch consistency, and production yield of the thermal barrier coating on turbine blades have become core indicators determining the service life and reliability of equipment. Currently, the tooling and processes used in the thermal spraying of turbine blades suffer from significant technical deficiencies, failing to meet the mass production requirements of high-end equipment. 1. Poor versatility and insufficient positioning accuracy of clamping fixtures: Traditional fixtures mostly use single-point / single-sided rigid clamping, which is prone to clamping offset and over-positioning problems due to the irregular tenon and edge plate curved surface structure of turbine blades. The repeatability of positioning accuracy is low (usually >0.1mm). Moreover, the fixtures are custom-designed, and different models of blades need to be molded and the entire fixture needs to be made again, which results in high R&D costs and long cycles, and cannot be adapted to flexible production of multiple models.

[0003] 2. Low clamping efficiency and poor protection: Traditional tooling takes more than 45 minutes to clamp a single blade, and the clamping structure easily blocks the spraying area. At the same time, it cannot effectively protect the non-spraying area, resulting in coating contamination and over-spraying. Subsequent grinding and removal processes are required, and the blade may even be scrapped.

[0004] 3. Poor controllability of coating thickness and low pass rate: The turbine blade body is a complex free-form surface, and the rim plate has irregular structures such as protrusions, corners, and transition R-arcs. The traditional continuous spraying process cannot ensure that the normal angle between the spray gun and all curved surfaces meets the spraying requirements. In particular, the intersection line between the blade body and the rim plate and the R-angle area are prone to problems such as thin coating and insufficient adhesion. The coating thickness uniformity is only about 80%, and the batch rework rate is as high as 30%, which cannot meet the quality requirements of high-end blades.

[0005] 4. Insufficient mass production stability: Traditional processes lack a closed-loop thickness control system, making it impossible to achieve real-time layer calibration. Coating quality fluctuates greatly during mass production, making it difficult to adapt to the continuous production needs of automated production lines.

[0006] This invention addresses the core pain points of the aforementioned prior art by using modular tooling design and a zoned closed-loop spraying process to achieve high-precision clamping of turbine blades and full-process controllability of coating quality, thus solving a long-standing technical problem in the industry. Summary of the Invention

[0007] The main objective of this invention is to provide a turbine blade spraying clamping fixture and spraying method, which can effectively solve the problems in the background art.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The turbine blade spraying clamping fixture includes a lower connecting rod, a lower frame, an upper frame, and an adjustable support assembly, a radial positioning assembly, and a counterweight balancing assembly, all assembled coaxially in sequence. The lower part of the lower connecting rod is a polygonal positioning column, which is used to cooperate with the positioner turntable to achieve precise circumferential angle positioning. The upper part is rigidly connected to the bottom of the lower frame through internal hexagonal connecting screws. The inner contour of the lower frame is adapted to the lower edge plate and the outer contour of the tenon of the blade to be sprayed. The adjustable support assembly is set in the inner cavities of the lower frame and the upper frame and is used to omnidirectionally tighten and limit the root tenon of the blade. The radial positioning component is a detachable structure and is installed on the movable side of the upper frame. The inner contour of the radial positioning component is adapted to the irregular outer contour of the upper edge plate of the blade to be sprayed, and is used to radially limit and clamp the upper edge plate of the blade. The counterweight balancing assembly is detachably fixed to the sides of the lower frame 2 and the upper frame 3 to balance the overall center of gravity of the tooling and the blade. Both the adjustable support assembly and the radial positioning assembly are adjusted and locked in position by locking components to adapt to turbine blades of different specifications.

[0009] Preferably, the lower connecting rod is a multi-segment coaxial structure made of 40Cr steel. The lower polygonal positioning column of the lower connecting rod is a hexagonal prism structure, which is used to fit the hexagonal positioning hole of the positioner turntable to achieve precise circumferential angle positioning. The upper part of the lower connecting rod is a quadrangular prism structure connected to the lower frame. An M8 threaded hole is opened at the top, and it is rigidly connected to the bottom of the lower frame through 4 internal hexagonal head screws.

[0010] Preferably, the adjustable support assembly includes a lower air intake side support block, a lower air outlet side support block, an upper air intake side support block, and an upper air outlet side support block; each support block is provided with an elongated adjustment slot, which is pre-positioned by a cylindrical positioning pin and locked by an internal hexagonal locking screw to achieve stepless adjustment of the support position.

[0011] Preferably, the radial positioning component is an upper inner radial block, which is detachably connected to the movable side of the upper frame by bolts and is a quick-change structure. Different specifications of upper inner radial blocks are adapted to the upper edge plate contours of different blade models.

[0012] Preferably, the counterweight balancing component is a steel counterweight block, and the number and position of the counterweight blocks can be adjusted according to the weight and center of gravity of the blade.

[0013] A method for spraying thermal barrier coatings on turbine blades includes the following steps: S1 Blade Pretreatment: The surface of the turbine blade to be coated is roughened by sandblasting to control the surface roughness Ra≤3.2μm, and the non-coated area is treated with high temperature shielding. S2 Clamping and Positioning: Install the pre-treated blades into the clamping fixture, adjust and lock the adjustable support assembly and radial positioning assembly, fix the fixture as a whole to the positioner turntable, and complete the circumferential angle calibration through the lower connecting rod; S3 Spraying Area Division: The surface of the turbine blade to be sprayed is divided into 9 independent spraying zones, specifically 1 zone each for the blade face and the blade back, 3 zones for the inlet side, outlet side, and end face of the upper edge plate, and 3 zones for the inlet side, outlet side, and end face of the lower edge plate; at the same time, the intersection area between the blade body and the upper and lower edge plates, and the transition R-angle area between the blade face and the blade back are divided into pre-spraying reinforcement areas; S4 Spraying Path and Parameter Preset: The spray gun path is planned for each independent spraying zone through robot programming, the normal angle between the spray gun and the corresponding spraying surface is controlled to be ≥75°, and the plasma spraying process parameters are preset. S5 Pre-coating reinforcement: The first layer of pre-coating is applied to the pre-coating reinforcement area. The thickness of the pre-coating layer is 20-30μm thicker than the thickness of the subsequent base layer. S6 Zoned Layer-by-Layer Spraying: Spraying is performed layer by layer on 9 independent spraying zones in a preset order. After each layer is completed, the coating thickness of the entire area is measured in real time. Areas with insufficient thickness are marked. When spraying the next layer, the marked areas are re-sprayed, and the areas that meet the thickness standard are shielded. S7 Thickness Calibration and Verification: The same batch of test pieces are used for dissection and verification. The coating thickness of the intersection line and transition R-angle area is calibrated, and the spraying path and parameters are adjusted until the coating thickness of the entire area meets the design requirements.

[0014] Preferably, in step S6, the preset spraying sequence is as follows: first spray the three sections of the upper edge plate, then spray the two sections of the leaf basin surface and the back of the leaf, and finally spray the three sections of the lower edge plate; wherein the spray guns of each section of the upper edge plate are in an upward angle and the spray guns of each section of the lower edge plate are in a downward angle.

[0015] Preferably, in step S4, the preset plasma spraying process parameters are: spray gun moving speed 200-1000mm / s, spraying distance 60-120mm, and plasma spraying power 20-50kW.

[0016] Preferably, in step S7, a coating thickness deviation of ≤10% across the entire area after calibration is considered acceptable.

[0017] Preferably, in step S6, the thickness of a single layer of coating applied layer by layer is 25-35 μm, and the final total coating thickness is designed to be 300±20 μm.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Significant improvement in clamping efficiency and precision: Through a modular omnidirectional adjustable structure and a frame design that adapts to the blade profile, precise clamping of blades without over-positioning is achieved. The clamping time for a single blade is reduced from the traditional 45 minutes to less than 15 minutes, and the clamping repeatability accuracy is ≤0.05mm, completely solving the coating defects caused by blade displacement during the spraying process.

[0019] 2. High tooling versatility and significantly reduced production costs: Through the stepless adjustment of the adjustable support components, combined with the quick-change upper inner radial block, only a few parts need to be replaced to adapt to different models of turbine blades. There is no need to redesign the entire tooling, reducing tooling R&D costs by more than 70%, significantly shortening the production cycle, and adapting to flexible mass production of multiple models.

[0020] 3. Significantly improved coating quality and pass rate: By adopting a 9-zone independent spraying strategy and combining it with a pre-spraying reinforcement process for irregularly shaped areas, the optimal spray gun posture is matched for different curved surfaces of the blade, solving the industry pain point of uneven coating thickness in complex curved surfaces and corner intersection areas in traditional processes; the coating thickness uniformity has been improved from the traditional 80% to over 95%, the batch rework rate has been reduced from 30% to less than 5%, and there are no blade scraps caused by coating contamination.

[0021] 4. Strong process stability and suitable for industrial mass production: Through a closed-loop thickness control system of layered real-time thickness measurement + targeted respraying + test piece dissection calibration, the coating thickness can be accurately controlled, and the coating quality is consistent in mass production; at the same time, the counterweight balance design ensures the stability of the positioner during high-speed rotation, which can be seamlessly adapted to the continuous production of automated spraying production lines and has extremely high industrial applicability. Attached Figure Description

[0022] Figure 1 : Schematic diagram of the blade basin side structure of the turbine blade of the present invention; Figure 2 : Schematic diagram of the back side structure of the turbine blade of the present invention; Figure 3 : A schematic diagram of the three-dimensional assembly structure of the turbine blade spraying clamping fixture of the present invention; Figure 4 : Front view of the turbine blade spraying clamping fixture of the present invention; Figure 5 : Figure 4 A schematic diagram of the internal structure of the upper and lower frames from a center-A perspective; Figure 6 : Figure 4 A schematic diagram of the internal structure of the upper and lower frames from a B-axis perspective; Figure 7 : Schematic diagram of the spraying zone division of the turbine blade of the present invention.

[0023] In the diagram: 1. Lower connecting rod; 2. Lower frame; 3. Upper frame; 4. Hex socket head cap screw; 5. Counterweight; 6. Lower air intake side support block; 7. Cylindrical locating pin; 8. Lower air outlet side support block; 9. Hex socket head cap locking screw; 10. Upper air outlet side support block; 11. Upper air intake side support block; 12. Upper inner radial block. Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0025] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Example Please see Figure 1-7 The present invention provides the following technical solution: The turbine blade spraying clamping fixture includes a lower connecting rod 1, a lower frame 2, and an upper frame 3, which are coaxially assembled in sequence, as well as an adjustable support assembly, a radial positioning assembly, and a counterweight balancing assembly. The lower part of the lower connecting rod 1 is a polygonal positioning column, which is used to cooperate with the positioner turntable to achieve precise circumferential angle positioning. The upper part is rigidly connected to the bottom of the lower frame 2 through the internal hexagonal connecting screw 4. The inner contour of the lower frame 2 is adapted to the lower edge plate and the outer contour of the tenon of the blade to be sprayed. The adjustable support assembly is set in the inner cavity of the lower frame 2 and the upper frame 3 to omnidirectionally tighten and limit the root tenon of the blade. The radial positioning component is a detachable structure and is installed on the movable side of the upper frame 3. The inner contour of the radial positioning component is adapted to the irregular outer contour of the upper edge plate of the blade to be sprayed, and is used to radially limit and clamp the upper edge plate of the blade. The counterweight balancing assembly is detachably fixed to the sides of the lower frame 2 and the upper frame 3 to balance the overall center of gravity of the tooling and the blade. Both the adjustable support assembly and the radial positioning assembly are adjusted and locked in position by locking components to adapt to turbine blades of different specifications.

[0028] Specifically, the lower connecting rod 1 is a multi-segment coaxial structure made of 40Cr steel. The lower polygonal positioning column of the lower connecting rod 1 is a hexagonal prism structure, which is used to fit the hexagonal positioning hole of the positioner turntable to achieve precise circumferential angle positioning. The upper part of the lower connecting rod 1 is a quadrangular prism structure connected to the lower frame 2. An M8 threaded hole is opened at the top, and it is rigidly connected to the bottom of the lower frame 2 by four internal hexagonal head screws 4.

[0029] Specifically, the adjustable support assembly includes a lower air intake side support block 6, a lower air outlet side support block 8, an upper air intake side support block 11, and an upper air outlet side support block 10; each support block is provided with an elongated adjustment slot, which is pre-positioned by a cylindrical positioning pin 7 and locked by an internal hexagonal locking screw 9 to achieve stepless adjustment of the support position.

[0030] Specifically, the radial positioning component is an upper inner radial block 12. The upper inner radial block 12 is detachably connected to the movable side of the upper frame 3 by bolts and is a quick-change structure. Different specifications of the upper inner radial block 12 are adapted to the upper edge plate contour of different models of blades.

[0031] Specifically, the counterweight balancing component is a steel counterweight 5, and the number and position of the counterweight 5 can be adjusted according to the weight and center of gravity of the blade.

[0032] 6. A method for spraying thermal barrier coatings on turbine blades, comprising the following steps: S1 Blade Pretreatment: The surface of the turbine blade to be coated is roughened by sandblasting to control the surface roughness Ra≤3.2μm, and the non-coated area is treated with high temperature shielding. S2 Clamping and positioning: Install the pre-treated blades into the clamping fixture, adjust and lock the adjustable support assembly and radial positioning assembly, fix the fixture as a whole to the positioner turntable, and complete the circumferential angle calibration through the lower connecting rod 1; S3 Spraying Area Division: The surface of the turbine blade to be sprayed is divided into 9 independent spraying zones, specifically 1 zone each for the blade face and the blade back, 3 zones for the inlet side, outlet side, and end face of the upper edge plate, and 3 zones for the inlet side, outlet side, and end face of the lower edge plate; at the same time, the intersection area between the blade body and the upper and lower edge plates, and the transition R-angle area between the blade face and the blade back are divided into pre-spraying reinforcement areas; S4 Spraying Path and Parameter Preset: The spray gun path is planned for each independent spraying zone through robot programming, the normal angle between the spray gun and the corresponding spraying surface is controlled to be ≥75°, and the plasma spraying process parameters are preset. S5 Pre-coating reinforcement: The first layer of pre-coating is applied to the pre-coating reinforcement area. The thickness of the pre-coating layer is 20-30μm thicker than the thickness of the subsequent base layer. S6 Zoned Layer-by-Layer Spraying: Spraying is performed layer by layer on 9 independent spraying zones in a preset order. After each layer is completed, the coating thickness of the entire area is measured in real time. Areas with insufficient thickness are marked. When spraying the next layer, the marked areas are re-sprayed, and the areas that meet the thickness standard are shielded. S7 Thickness Calibration and Verification: The same batch of test pieces are used for dissection and verification. The coating thickness of the intersection line and transition R-angle area is calibrated, and the spraying path and parameters are adjusted until the coating thickness of the entire area meets the design requirements.

[0033] Specifically, in step S6, the preset spraying sequence is as follows: first spray the three sections of the upper edge plate, then spray the two sections of the leaf basin surface and the back of the leaf, and finally spray the three sections of the lower edge plate; wherein the spray guns of each section of the upper edge plate are in an upward angle, and the spray guns of each section of the lower edge plate are in a downward angle.

[0034] Specifically, in step S4, the preset plasma spraying process parameters are: spray gun moving speed 200-1000mm / s, spraying distance 60-120mm, and plasma spraying power 20-50kW.

[0035] Specifically, in step S7, a coating thickness deviation of ≤10% across the entire area after calibration is considered acceptable.

[0036] Specifically, in step S6, the thickness of each single layer of coating sprayed layer by layer is 25-35μm, and the final total coating thickness is designed to be 300±20μm.

[0037] Example 1: Specific Implementation of Clamping Fixture The turbine blade spraying clamping fixture of this embodiment is used for plasma spraying clamping of K452 alloy turbine blades of a certain type of gas turbine, and its structure is as follows: Figure 3-5 As shown, the specific assembly and implementation methods are as follows: 1. The lower connecting rod 1 adopts a multi-segment coaxial structure made of 40Cr steel. The lower part is a hexagonal prism structure, which is adapted to the hexagonal positioning hole of the positioner turntable, so as to achieve precise circumferential angle positioning and avoid angle deviation during the spraying process. The upper part is a square prism structure with an M8 threaded hole at the top. It is rigidly connected to the bottom of the lower frame 2 through 4 internal hexagonal connecting screws 4, ensuring coaxiality and rotational rigidity of the connection, and no shaking or gap.

[0038] 2. The lower frame 2 is an integral U-shaped steel frame. The inner cavity contour is perfectly matched with the lower edge plate and tenon outer contour of the blade to be sprayed, which not only achieves the initial positioning of the blade, but also avoids the frame from blocking the area to be sprayed. The lower air intake side support block 6 and the lower air outlet side support block 8 are respectively installed on both sides of the inner cavity of the lower frame 2. The two support blocks correspond to the air intake side and air outlet side of the blade tenon, respectively. The support blocks are provided with long strip adjustment waist holes. They are pre-positioned by φ4 cylindrical positioning pins 7 and locked by M6 internal hexagon locking screws 9, which can achieve stepless adjustment within ±5mm range, and tighten the side of the blade tenon to limit the axial and radial displacement of the blade.

[0039] 3. After the upper frame 3 and the lower frame 2 are assembled, they are locked with four M8 bolts. The upper air intake side support block 11 and the upper air outlet side support block 10 are installed in the inner cavity of the upper frame 3. They cooperate with the two support blocks of the lower frame to achieve omnidirectional clamping of the blade tenon in four directions (up, down, left, and right) without any loosening gaps. The movable side of the upper frame 3 is provided with a T-shaped mounting groove. The upper inner radial block 12 is detachably fixed in the mounting groove by two M6 bolts. The inner contour of the upper inner radial block 12 is fully fitted with the irregular protruding outer contour of the upper edge plate of the blade to be sprayed through five-axis machining, forming a precise radial limit on the upper edge plate of the blade to prevent the blade from deflecting during the spraying process. The upper inner radial block 12 is a quick-change structure. For different blade models, only the upper inner radial block 12 with the corresponding contour needs to be replaced to achieve tooling adaptation without replacing the entire frame.

[0040] 4. The counterweight 5 is a steel counterweight with a single weight of 500g. It is detachably fixed to the side of the lower frame 2 and the upper frame 3 by means of hexagonal screws. In this embodiment, according to the weight and center of gravity of the blade, two counterweights are installed on the opposite side of the lower frame to balance the overall center of gravity of the tooling and the blade, ensuring that the tooling does not shake or become eccentric during the rotation of the positioner turntable from 0 to 120 r / min, thereby improving the stability of the spraying process.

[0041] Example 2: Specific Implementation of the Spraying Method This embodiment uses the clamping fixture from Embodiment 1 to prepare a YSZ thermal barrier coating on the turbine blades of the same type of gas turbine. The total coating thickness is designed to be 300±20μm. The specific implementation steps are as follows: 1. Blade pretreatment: The surface of the blade to be coated is ultrasonically cleaned with anhydrous alcohol for 15 minutes to remove surface oil and impurities, and then dried with cold air; subsequently, it is roughened by sandblasting with 80# white corundum sand at a sandblasting pressure of 0.5MPa and a sandblasting distance of 150mm, controlling the surface roughness Ra=2.8-3.2μm to ensure the adhesion between the coating and the substrate; the tenons, non-coated edge plate end faces, mounting holes and other non-coated areas of the blade are fully covered and shielded with 0.08mm thick high-temperature resistant metal tape to avoid coating contamination.

[0042] 2. Clamping and Positioning: Place the pre-treated blade root tenon into the inner cavity of the lower frame 2, adjust the position of the lower intake side support block 6 and the lower exhaust side support block 8 so that the support blocks are completely in contact with the side of the blade tenon, and pre-tighten the hexagonal locking screws 9; then install the upper frame 3, adjust the upper intake side support block 11 and the upper exhaust side support block 10, and clamp the blade tenon with the lower support block, and tighten all locking screws; install the corresponding model of upper inner radial block 12, and after locking, manually confirm that the blade has no axial, radial, or circumferential displacement or deflection; insert the tooling with the assembled blade into the positioning hole of the positioner turntable through the lower connecting rod 1, calibrate the circumferential 0° reference, lock the turntable, install the counterweight to balance the center of gravity, and complete the clamping.

[0043] 3. Spraying area division: such as Figure 6 As shown, the surface of the blade to be coated is divided into 9 independent coating zones: zone 1 for the blade basin, zone 2 for the blade back, zone 3 for the air inlet side of the upper edge plate, zone 4 for the air outlet side of the upper edge plate, zone 5 for the upper upper edge plate, zone 6 for the air inlet side of the lower edge plate, zone 7 for the air outlet side of the lower edge plate, and zone 8 for the lower lower edge plate. At the same time, the annular intersection line between the blade body and the upper and lower edge plates, and the R-angle of the air inlet and outlet sides of the blade basin and blade back are divided into pre-coating reinforcement areas.

[0044] 4. Spraying path and parameter preset: An ABB six-axis spraying robot is used for offline programming. Independent reciprocating travel paths of the spray guns are planned for each of the nine zones to ensure that the angle between the spray gun axis and the normal of the corresponding spraying surface is always ≥75°. Among them, the spray guns in zones 3-5 (upper edge plate) adopt an upward 75°-85° posture, the spray guns in zones 6-8 (lower edge plate) adopt a downward 75°-85° posture, and the blade basin and blade back areas adopt a reciprocating path along the blade profile to ensure that the spraying distance and angle are consistent throughout the curved surface.

[0045] Preset core process parameters for plasma spraying: spray gun moving speed 300mm / s, spraying distance 110mm, plasma spraying power 30kW, main gas (Ar) flow rate 40L / min, auxiliary gas (H2) flow rate 10L / min, powder feeding amount 30g / min, single-layer base spraying thickness 30μm.

[0046] 5. Pre-coating reinforcement: First, a first layer of pre-coating is applied to the pre-coating reinforcement area, using the same process parameters as the base layer. The pre-coating thickness is 50μm, which is 20μm thicker than the base single layer. This strengthens the coating deposition in corner and intersection areas, preventing insufficient thickness in these areas during subsequent spraying.

[0047] 6. Zoned Layer-by-Layer Spraying: Spray the coating layer by layer in the order of "Upper Edge Plate Zones 3-5 → Blade Basin Zone 1 + Blade Back Zone 2 → Lower Edge Plate Zones 6-8". After each layer is completed, use an eddy current thickness gauge to measure the thickness of the entire area in a grid pattern (grid spacing 5mm). Mark the areas where the thickness is lower than the design limit. When spraying the next layer, only the marked unqualified areas are re-sprayed. For areas that have reached the design thickness, use a high-temperature resistant ceramic shielding cover for temporary shielding to avoid over-spraying.

[0048] Repeat the above process of spraying, measuring thickness, and re-spraying layer by layer until the average coating thickness of the entire area reaches 300μm, with a total of 10 layers sprayed.

[0049] 7. Thickness Calibration and Verification: The same batch, material, clamping, and process as the product blades were used for in-furnace test specimens for dissection and verification. The intersection area and transition R-angle area of ​​the test specimens were resin-mounted, sliced, and polished. The actual coating thickness was measured using a metallographic microscope. In this embodiment, the maximum thickness deviation in this area was 7.2%, which meets the design requirement of ≤10% and no process adjustment is required. If the deviation exceeds the requirement, the robot path, spray gun angle, and number of spray passes need to be adjusted accordingly until it is qualified.

[0050] 8. Post-processing and inspection: After spraying, remove the blades, remove the high-temperature shielding tape from the non-sprayed areas, and perform visual inspection on the coating to ensure that the coating is free of cracks, chips, and overspray contamination. Use an eddy current thickness gauge to re-inspect the thickness of the entire area, and use the tensile method to test the coating adhesion. In this embodiment, the coating adhesion is ≥45MPa, and the thickness deviation of the entire area is ≤8%, which meets the design requirements. After passing the test, proceed to the next process.

[0051] Implementation effect verification The following is a comparison between this embodiment and traditional tooling and processes:

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A turbine blade spray clamping fixture, characterized by, It comprises a lower connecting rod (1), a lower frame (2), an upper frame (3) which are coaxially assembled in sequence, an adjustable support assembly, a radial positioning assembly and a counterweight balancing assembly; The lower part of the lower connecting rod (1) is a multi-edge positioning cylinder which is used for cooperating with the rotating disc of the positioner to realize accurate positioning in the circumferential direction; the upper part is rigidly connected with the bottom of the lower frame (2) through an inner hexagonal connecting screw (4). The inner cavity contour of the lower frame (2) is matched with the lower edge plate and the tenon of the blade to be sprayed; the adjustable support assembly is arranged in the inner cavity of the lower frame (2) and the upper frame (3) and is used for all-directionally clamping and limiting the root tenon of the blade. The radial positioning assembly is a detachable structure and is installed on the movable side of the upper frame (3); the inner contour of the radial positioning assembly is matched with the irregular outer contour of the upper edge plate of the blade to be sprayed and is used for radially limiting and clamping the upper edge plate of the blade. The counterweight balancing assembly is detachably fixed on the side edges of the lower frame (2) and the upper frame (3) and is used for balancing the overall gravity center of the tooling and the blade. The adjustable support assembly and the radial positioning assembly are adjusted and locked through locking members to adapt to turbine blades of different specifications.

2. The turbine blade spray clamping fixture of claim 1, wherein, The lower connecting rod (1) is a multi-section coaxial structure made of 40Cr steel; the lower multi-edge positioning cylinder of the lower connecting rod (1) is a hexagonal prism structure which is used for adapting the hexagonal positioning hole of the rotating disc of the positioner to realize accurate positioning in the circumferential direction; the upper part of the lower connecting rod (1) is a four-edge prism structure which is connected with the lower frame (2) and is provided with an M8 threaded hole at the top and is rigidly connected with the bottom of the lower frame (2) through four inner hexagonal connecting screws (4).

3. The turbine blade spray clamping fixture of claim 1, wherein, The adjustable support assembly comprises a lower air inlet side support block (6), a lower air outlet side support block (8), an upper air inlet side support block (11) and an upper air outlet side support block (10); each support block is provided with a long strip adjusting waist hole and is pre-positioned through a cylindrical positioning pin (7) and locked through an inner hexagonal locking screw (9) to realize stepless adjustment of the support position.

4. The turbine blade spray clamping fixture of claim 1, wherein, The radial positioning assembly is an upper inner radial block (12) which is detachably connected with the movable side of the upper frame (3) through a bolt and is a quick-change structure; different specifications of the upper inner radial block (12) correspond to the upper edge plate contour of blades of different types.

5. The turbine blade spray clamping fixture of claim 1, wherein, The counterweight balancing assembly is a steel counterweight block (5); the number and position of the counterweight block (5) can be adjusted according to the weight and gravity center of the blade.

6. A method of thermal barrier coating spray application for turbine blades, characterized in that, The turbine blade spraying clamping tooling based on any one of claims 1-5 comprises the following steps: S1 Blade pretreatment: the surface of the turbine blade to be sprayed is subjected to sand blasting roughening treatment to control the surface roughness Ra≤3.2μm; the non-spraying area is subjected to high-temperature resistant shielding treatment; S2 Clamping and positioning: the pretreated blade is installed to the clamping tooling, the adjustable support assembly and the radial positioning assembly are adjusted and locked, the tooling is fixed on the rotating disc of the positioner, and the circumferential angle calibration is completed through the lower connecting rod (1). S3 Spraying area division: The surface to be sprayed of the turbine blade is divided into 9 independent spraying zones, specifically 1 zone for the blade basin surface and 1 zone for the blade back surface, 3 zones for the inlet side surface, outlet side surface and end surface of the upper edge plate, and 3 zones for the inlet side surface, outlet side surface and end surface of the lower edge plate; at the same time, the intersection line area of the blade body and the upper and lower edge plates and the transition R angle area of the blade basin and the blade back are divided into pre-spraying strengthening areas; S4 Spraying path and parameter presetting: The spraying gun path is planned for each independent spraying zone through robot programming, the normal angle between the spraying gun and the corresponding spraying surface is controlled to be greater than or equal to 75°, and the plasma spraying process parameters are preset; S5 Pre-spraying strengthening: The first layer of pre-spraying is performed on the pre-spraying strengthening area, and the pre-sprayed coating thickness is increased by 20-30 μm compared with the subsequent single layer thickness; S6 Layer-by-layer spraying in zones: The 9 independent spraying zones are sprayed layer by layer in the preset order, the coating thickness of the whole area is measured in real time after each layer of spraying is completed, the areas with non-compliant thickness are marked, the marked areas are supplemented during the next layer of spraying, and the areas that meet the requirements are shielded; S7 Thickness calibration and verification: The same batch of test pieces are used for dissection verification, the coating thickness of the intersection line and the transition R angle area is calibrated, the spraying path and parameters are adjusted until the coating thickness of the whole area meets the design requirements.

7. The method of claim 6, wherein the method further comprises, In step S6, the preset spraying order is: first, spraying the 3 zones of the upper edge plate, then spraying the 2 zones of the blade basin surface and the blade back surface, and finally spraying the 3 zones of the lower edge plate; wherein the spraying gun of each zone of the upper edge plate adopts an oblique upward posture, and the spraying gun of each zone of the lower edge plate adopts an oblique downward posture.

8. The method of claim 6, wherein the method further comprises, In step S4, the preset plasma spraying process parameters are: spraying gun moving speed 200-1000 mm / s, spraying distance 60-120 mm, and plasma spraying power 20-50 kW.

9. The method of claim 6, wherein the method further comprises, In step S7, the whole area coating thickness deviation after calibration is less than or equal to 10% to be qualified.

10. The method of claim 6, wherein, In step S6, the single layer coating thickness of layer-by-layer spraying is 25-35 μm, and the final coating design total thickness is 300±20 μm.

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