Turbine last-stage blade and preparation method

Abstract

The invention discloses a last-stage blade of a steam turbine and a preparation method, and aims to solve the problems of stress concentration, insufficient vibration resistance and serious wet steam water erosion of a fir tree-shaped blade root transition fillet of an existing blade. Each blade comprises a blade top, a blade body, a blade root and a transition section connecting the blade body and the blade root, and the blade root is of a fir-tree-shaped structure formed by meshing teeth on the two sides of the transition section. Mounting grooves in one-to-one correspondence with the transition fillets are formed in the non-bearing surface, facing the impeller groove, of the transition section, honeycomb damping modules with honeycomb hole arrays and damping materials are embedded in the grooves, a positioning structure is arranged between the honeycomb damping modules and the honeycomb damping modules, and the areas such as the transition fillets are covered with TiAlN anti-corrosion coatings. The preparation method comprises the steps of blade integrated die forging, damping module additive manufacturing, low-temperature assembling and coating laser cladding. Stress can be dispersed, resonance is restrained, water erosion is resisted, the blade performance is improved, the service life is prolonged, and reliable operation of a steam turbine is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam turbine blades, in particular to a steam turbine last stage blade and a preparation method. BACKGROUND

[0002] The steam turbine last stage blade is a core working component of the steam turbine, which undertakes the key task of steam energy conversion, and its working performance directly affects the operation efficiency and reliability of the steam turbine. Its working environment is extremely complex, it needs to withstand the huge centrifugal force generated by high-speed rotation, the erosion of wet steam and the load fluctuation brought by variable working conditions, and also needs to cope with the vibration influence caused by steam pulsation, which puts strict requirements on structural strength, anti-vibration performance and corrosion resistance.

[0003] In order to meet the bearing requirements of the last stage blade, the fir tree root structure is widely used in the prior art, which is matched with the impeller groove through the multi-tooth meshing mode, has the characteristics of strong bearing capacity and relatively uniform stress distribution, and is suitable for the fixation and power transmission of long-size last stage blades.

[0004] However, the transition fillet area of the fir tree root is always a weak link, since the area is designed as a rigid connection, the stress transmission path is prone to dense superposition at this point, forming a significant stress concentration phenomenon, and under the action of long-term alternating load, fatigue cracks are easily generated, and in severe cases, the blade may be broken and failed.

[0005] At the same time, the existing last stage blade is a rigid structure as a whole, and lacks effective vibration energy dissipation mechanism. When the excitation force frequency generated by steam pulsation is close to the natural frequency of the blade, resonance is easily induced, which not only amplifies the stress concentration effect, but also intensifies the impact of the blade and the condensate water droplets in the wet steam on the material surface, further weakening the material surface strength, accelerating crack propagation and structural failure. SUMMARY

[0006] The main purpose of the present application is to provide a steam turbine last stage blade and a preparation method, which aims at the problems of stress concentration in the transition fillet of the existing steam turbine last stage blade, lack of effective anti-vibration mechanism and serious wet steam erosion damage, by setting an installation groove matched with the transition fillet and an embedded honeycomb damping module on the non-bearing surface of the transition section, and cooperating with the positioning structure and TiAlN anti-erosion coating, the stress concentration, vibration resonance and water erosion defects of the blade are simultaneously improved.

[0007] To achieve the above object, the application provides a last-stage blade of a steam turbine, which comprises a blade top, a blade body and a blade root, a transition section is arranged between the blade body and the blade root, the transition section is used for connecting the blade root and the blade body, the blade root is composed of a plurality of meshing teeth which are arranged on both sides of the transition section to form a fir tree tooth structure, a plurality of mounting grooves are arranged on a non-load bearing surface of one end of the transition section, and a transition fillet formed between each pair of meshing teeth and the mounting grooves corresponds to each other, and a honeycomb damping module is embedded in the mounting grooves. Wherein, the non-load bearing surface is a surface of one end of the transition section facing a wheel groove of an impeller; the transition fillet is a circular arc structure formed by smoothly connecting a tooth top edge of each pair of adjacent meshing teeth and a surface of the transition section, and the transition fillet is a stress concentration area of the blade.

[0008] In a possible implementation, the mounting groove is a groove structure, and a positioning structure is arranged between the mounting groove and the honeycomb damping module.

[0009] In a possible implementation, the honeycomb damping module is tightly fitted with the mounting groove, the honeycomb damping module comprises a main body part matched with the mounting groove, a honeycomb hole array is arranged on the main body part, and a damping material is filled in the honeycomb hole array for dissipating vibration energy of the blade.

[0010] In a possible implementation, the positioning structure comprises positioning grooves opened in opposite side walls of the mounting groove, and elastic clamping claws arranged on both sides of the main body part and clamped with the positioning grooves.

[0011] In a possible implementation, the positioning structure comprises positioning holes arranged in the bottom of the mounting groove, and positioning pins arranged in the bottom of the main body part and matched with the positioning holes in a interference fit.

[0012] In a possible implementation, an anti-corrosion coating is further included, which covers surfaces of the transition fillet, an outer surface of the honeycomb damping module and a fitting gap between the honeycomb damping module and the mounting groove, and is used for resisting water drop impact and medium corrosion in a wet steam environment.

[0013] In a possible implementation, the anti-corrosion coating is a TiAlN coating, the thickness of the TiAlN coating is 0.3-0.5mm, the hardness is greater than or equal to HRC65, and the bonding strength between the coating and the substrate is greater than or equal to 50MPa.

[0014] To realize the preparation of the last-stage blade of the steam turbine, the application further provides a preparation method of the last-stage blade of the steam turbine, which comprises the following steps: S1, blade body preparation: first, 12Cr stainless steel or GH696 high-temperature alloy forging blank is selected as the blank, the blank is quenched and tempered, and then forged into an integrated structure of blade top, blade body, transition section and blade root; then, a mounting groove is machined on the non-load-bearing surface of the transition section by numerical control milling, and a positioning groove and a positioning hole are machined in the mounting groove; S2, honeycomb damping module manufacturing: using additive manufacturing technology to form a module body containing elastic clamping jaws and positioning pins, after machining the honeycomb hole array on the module body, filling high-temperature metal rubber damping material into the hole, and then vacuum pressure compaction and solidification; S3, module assembly; embed the honeycomb damping module into the mounting groove, so that the elastic clamping jaw is clamped into the positioning groove, and the positioning pin is pressed into the positioning pin hole, to realize the close fixing of the module and the mounting groove.

[0015] S4, preparation of corrosion-resistant coating: using laser cladding technology to prepare TiAlN coating on the transition fillet of the blade after S3 step, the outer surface of the honeycomb damping module and the gap, and finally complete the preparation of the blade.

[0016] In a possible implementation, in the S3 step, the honeycomb damping module is first cooled by liquid nitrogen and then embedded into the mounting groove.

[0017] In a possible implementation, in step S4, argon is used as the protective gas during the cladding process, and polishing treatment is performed after the coating is formed.

[0018] In summary, the beneficial effects of the present application are: Compared with the prior art, the present application sets a mounting groove corresponding to the transition fillet on the non-load-bearing surface of the transition section towards the impeller groove, and embeds a honeycomb damping module with a honeycomb hole array and damping material, which can effectively disperse the stress concentration in the transition fillet area, suppress blade vibration resonance, and avoid crack initiation caused by the superposition of alternating load and resonance, by means of the stress diversion characteristics of the honeycomb structure and the energy dissipation effect of the damping material; in combination with the double positioning structure of the elastic clamping jaw and the positioning pin, the honeycomb damping module and the mounting groove are tightly fixed to ensure the stability of the structure; and then the TiAlN corrosion-resistant coating covering the transition fillet, the outer surface of the module and the gap can resist the impact of wet steam droplets and medium corrosion due to its high hardness and strong bonding force, and the above-mentioned structure synergistically improves the structural strength, anti-vibration performance and corrosion resistance of the blade, prolongs the service life of the blade, and further ensures the operating efficiency and reliability of the steam turbine. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the drawings shown without creative labor.

[0020] Figure 1 is a perspective view of the present application; Figure 2 is a back view of the present application; Figure 3 is Figure 2 is an enlarged view of A; Figure 4 is a structure view of the transition section and the blade root of the present application; Figure 5 is an internal structure view of the mounting groove of the present application; Figure 6 is a perspective view of the honeycomb damping module of the present application; Figure 7 is a structure view of the honeycomb damping module of the present application; Explanation of reference numerals: 1, blade tip; 2, blade body; 3, blade root; 4, transition section; 5, engaging tooth; 6, non-bearing surface; 7, mounting groove; 8, honeycomb damping module; 80, main body part; 81, damping material; 9, transition fillet; 10, positioning groove; 11, elastic clamping jaw; 12, positioning pin; 13, positioning hole.

[0021] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0023] Embodiment 1

[0024] As Figures 1-7As shown, the embodiment discloses a last-stage blade of a steam turbine, which is integrally formed by 12Cr stainless steel and sequentially includes a tip 1, a blade body 2, a transition section 4 and a root 3 in the longitudinal direction, and each part is seamlessly connected by a die forging process to ensure the structural integrity during high-speed rotation. The tip 1 is the aerodynamic end of the blade and is designed in a streamline shape to reduce the steam flow resistance; the blade body 2 is the core aerodynamic area, and the surface curvature thereof is optimized to efficiently guide the steam expansion work and convert the heat energy of the steam into mechanical energy of the blade. The transition section 4 is located between the bottom of the blade body 2 and the top of the root 3, which not only realizes the smooth transition of the blade body 2 and the root 3, but also provides a stable carrier for the subsequent installation structure, and the side of the transition section 4 facing the wheel groove of the impeller is a non-bearing surface 6, which does not participate in load transmission and only plays a connecting and positioning role. During the actual installation process, a gap of 0.3-0.5 mm is maintained between the non-bearing surface 6 and the wheel groove of the impeller to avoid assembly interference.

[0025] The root 3 adopts the mainstream industrial fir-tooth structure and is composed of multiple pairs of meshing teeth 5 symmetrically distributed on both sides of the transition section 4. The tooth surface of the meshing teeth 5 is precisely ground to ensure close fitting with the tooth surface of the wheel groove of the impeller, and the centrifugal force and steam force are uniformly transmitted to the impeller through the multi-tooth cooperative bearing mode. Although this structure solves the basic bearing problem, it has inherent technical defects. The edge of the tooth top of each pair of adjacent meshing teeth 5 and the surface connection of the transition section 4 facing the blade body 2 needs to form a transition round corner 9 through an arc transition, and the transition round corner 9 is the stress concentration core area of the blade. During the operation of the blade, the stress transmission path will be densely superimposed at this position. The traditional rigid structure lacks a stress dispersion mechanism and is prone to fatigue cracks when subjected to alternating loads for a long time, which may eventually lead to blade fracture failure. This is the primary technical problem to be overcome by the embodiment.

[0026] And the application, Figures 2-5 As shown, the embodiment clearly limits the improvement area to the non-bearing surface 6 of the transition section 4. The non-bearing surface 6 is the side surface of the transition section 4 facing the wheel groove of the impeller, which does not participate in the transmission of the core load of the blade and only bears the transition connection function. Processing the structure in this area can reduce the reduction of the strength of the root 3.

[0027] Specifically, an installation groove 7 corresponding to the transition round corner 9 is formed on the non-bearing surface 6, and the projection range of each installation groove 7 overlaps the corresponding transition round corner 9; the installation groove 7 is a blind groove that does not penetrate the transition section 4, and a double positioning structure is arranged in the groove: a double positioning structure is arranged in the groove, which not only provides a stable installation reference for the functional module, but also avoids damaging the overall structural strength of the transition section 4.

[0028] A honeycomb damping module 8 is embedded in the mounting groove 7 in interference fit with the groove body. The module is formed by additive manufacturing technology using high-temperature alloy. The main body 80 is fully compatible with the mounting groove 7 in shape, ensuring the continuity of stress transmission. The main body 80 is provided with an integrally formed elastic clamping jaw 11 and a positioning pin 12 at the position corresponding to the positioning structure of the mounting groove 7, which are double-fixed with the positioning groove 10 and the positioning hole 13 of the mounting groove 7, respectively. The elastic clamping jaw 11 is clamped into the positioning groove 10 by elastic deformation, limiting the loosening of the module along the groove width direction. The positioning hole 13 and the positioning pin 12 are in interference fit, constraining the displacement of the module along the groove depth direction. This double positioning design solves the technical problem of “easy loosening under high-speed vibration” in traditional module assembly, ensuring long-term stability of the structure.

[0029] As shown in Figures 6-7 The main body 80 of the module is provided with a regular hexagonal honeycomb hole array on the side away from the transition section 4. The holes are filled with high-temperature metal rubber damping material 81. When the concentrated stress transmitted by the transition fillet 9 acts on the module, the truss-type hole wall of the honeycomb hole array decomposes the single stress transmission path into multiple branch paths, so that the stress is uniformly dispersed to the mounting groove 7 and the body of the transition section 4, thereby fundamentally relieving stress concentration. When the blade vibrates due to steam pulsation, the vibration energy causes the main body 80 of the module to deform slightly, and the metal rubber filaments in the holes also deform elastically and rub against each other, thereby converting the vibration mechanical energy into heat energy and dissipating it. At the same time, the honeycomb structure changes the local mass and stiffness distribution of the blade, so that the natural frequency of the blade is dispersed into a continuous frequency band, avoiding the excitation frequency of the steam pulsation, and solving the inherent defect of the traditional rigid blade “easy resonance”.

[0030] In view of the water erosion and corrosion problem in the wet steam environment, the TiAlN anti-corrosion coating is covered on the key area in the embodiment. The coating coverage range includes not only the transition fillet 9 and the outer surface of the module, but also extends to the joint gap between the module and the mounting groove 7. This “comprehensive coverage + gap sealing” design is an optimization and upgrade of the traditional local protection.

[0031] The TiAlN coating has high hardness and strong bonding force, which can directly resist the impact of condensed water droplets in wet steam, and prevent plastic deformation and peeling of the transition fillet 9 and the surface of the module. The strong bonding force ensures that the coating does not fall off under vibration conditions, and cooperates with the sealing effect of the joint gap to isolate the contact between the wet steam and the substrate, prevent oxidation and electrochemical corrosion, and solve the technical pain point of the traditional blade “water erosion accelerating crack propagation”.

[0032] In this embodiment, during blade assembly, the fir-tree-shaped teeth of the blade root 3 precisely mesh with the impeller groove, and the non-load-bearing surface 6 of the transition section 4 maintains a gap with the groove, ensuring that the functional structure does not affect normal assembly. Through the structural synergy of "precise positioning mounting groove 7 + honeycomb damping module 8 + dual positioning + comprehensive anti-corrosion coating", the load-bearing advantages of the fir-tree-shaped blade root 3 are preserved, while its three core defects of "stress concentration, easy resonance, and poor corrosion resistance" are specifically addressed, significantly improving the blade's fatigue life and operational reliability, breaking through the performance bottleneck of traditional last-stage blades.

[0033] Example 2

[0034] The preparation method disclosed in this embodiment is specifically designed for the turbine last-stage blade structure of Embodiment 1. A preparation method for the last-stage blade of a turbine is disclosed, and the specific preparation process is as follows: As a fundamental process, blade body fabrication begins with raw material selection and pretreatment. Suitable alloy forging blanks are selected as raw materials, and the blank material must match the blade's high-temperature load-bearing and corrosion-resistant requirements. In the pretreatment stage, the forging blank is heated to a suitable temperature in a furnace and held there. Subsequently, oil cooling and tempering are used to control the forging blank's hardness, ensuring the plasticity required for subsequent die forging processes and laying the foundation for the blade's mechanical properties. The die forging process uses a customized mold with a cavity that perfectly matches the overall shape of the blade. The tempered forging blank is placed in the mold, and matching pressure is applied under high temperature to complete the die forging. After holding the pressure for a period, it is slowly cooled to room temperature in the furnace, resulting in a single-piece blank comprising the blade tip 1, blade body 2, transition section 4, and blade root 3. This one-piece molding ensures the structural integrity of the blade during high-speed rotation. After shot blasting to remove the surface oxide scale, the initial blank is transferred to the finishing stage: using the aerodynamic reference surface of blade 2 as the positioning reference, the surface of blade 2 is milled to the designed curvature using a five-axis CNC milling machine to ensure the surface accuracy required for aerodynamic performance; then, using the tooth surface of blade root 3 as the reference, the mounting groove 7 corresponding to the number of transition fillets 9 is milled on the non-load-bearing surface 6 of transition section 4, and the positioning groove 10 is machined on the side wall of mounting groove 7 and the positioning hole 13 is machined on the bottom of the groove. The dimensions of each structure are precisely controlled by the CNC system to ensure the assembly compatibility of the positioning structure with the subsequent modules.

[0035] After the blade body is prepared, the manufacturing process of the honeycomb damping module 8 begins. The module uses high-temperature performance alloy powder as raw material, and selective laser melting additive manufacturing technology is employed to form the main body 80. This technology precisely integrates the elastic claw 11 and the positioning pin 12, ensuring structural dimensional accuracy. After forming, the main body 80 is placed in a vacuum furnace for heat treatment to eliminate internal stress generated during additive manufacturing and improve structural stability. Subsequently, a regular hexagonal honeycomb array is machined on a designated surface of the main body 80 using a high-speed milling tool. After the array is machined, high-temperature metal rubber cut to the appropriate size is filled into the honeycomb holes and then placed in a vacuum press. Pressure is applied under vacuum to compact the metal rubber, while heating and heat preservation are used to complete the curing process, ensuring a tight bond between the metal rubber and the hole walls, preventing loosening or detachment during vibration.

[0036] The module assembly process requires cryogenic assistance to achieve precise positioning of the interference fit. First, the honeycomb damping module 8 is placed in liquid nitrogen for cryogenic treatment. The volume shrinkage effect caused by the low temperature allows the module to easily embed into the mounting slot 7. After the module naturally returns to room temperature within the mounting slot 7, its volume rebounds, achieving a tight interference fit with the mounting slot 7. Simultaneously, the elastic claws 11 of the main body 80 engage with the positioning slots 10 of the mounting slot 7 during the rebound process, and the bottom positioning pin 12 forms a stable fit with the positioning holes 13 of the mounting slot 7. This dual positioning structure ensures that the module has no risk of displacement or loosening under high-speed blade vibration conditions. After assembly, the module's installation accuracy and stability are verified using precision testing instruments.

[0037] As the final protective process, the anti-corrosion coating is prepared by laser cladding technology to create a TiAlN coating in a designated area. Before cladding, the surface of the transition fillet 9, the outer surface of the honeycomb damping module 8, and the mating gap between the module and the mounting groove 7 need to be pretreated. This involves sequentially cleaning with alcohol to remove oil and sandblasting to roughen the surface. The roughening process improves the adhesion between the coating and the substrate.

[0038] During the cladding process, a high-purity inert gas is used as a protective gas to prevent oxidation of the cladding area at high temperatures. TiAlN powder is uniformly fed to the cladding area using a dedicated powder feeding device, and the high-temperature energy of the laser is used to fuse the powder with the substrate surface, forming a continuous and uniform coating. After the coating is formed, it is precision polished with a diamond wheel to remove surface slag and protrusions, ensuring a smooth and flat coating surface and avoiding airflow disturbances during operation, thus completing the fabrication of the entire blade.

[0039] The fabrication method in this embodiment achieves the organic integration of the blade's basic structure, functional modules, and protective coating through precise coordination of each process. Additive manufacturing technology ensures the molding accuracy of the complex honeycomb damping module 8 structure, cryogenic assembly solves the assembly challenges of interference fits, and inert gas-protected cladding ensures the density and bonding strength of the corrosion-resistant coating. The blades fabricated using this method have structural features that highly match the design requirements, and can stably perform the synergistic functions of stress dispersion, vibration suppression, and corrosion protection, fully meeting the stringent operating requirements of turbine last-stage blades.

[0040] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0041] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A turbine last-stage blade, comprising a blade tip (1), a blade body (2), and a blade root (3), wherein a transition section (4) is provided between the blade body (2) and the blade root (3), the transition section (4) being used to connect the blade root (3) and the blade body (2), characterized in that, The leaf root (3) is composed of several meshing teeth (5), which are arranged on both sides of the transition section (4) to form a fir tree-shaped tooth structure. Several mounting grooves (7) are provided on the non-load-bearing surface (6) at one end of the transition section (4). The several mounting grooves (7) correspond one-to-one with the transition fillet (9) formed between each pair of meshing teeth (5), and a honeycomb damping module (8) is embedded in the mounting groove (7). Wherein, the non-load-bearing surface (6) is the end surface of the transition section (4) facing the impeller groove; the transition fillet (9) is the arc structure formed by the smooth connection between the tooth tip edge of each pair of adjacent meshing teeth (5) and the surface of the transition section (4); the transition fillet (9) is the stress concentration area of ​​the blade.

2. The turbine last-stage blade according to claim 1, characterized in that, The mounting groove (7) is a groove structure, and a positioning structure is provided between the mounting groove (7) and the honeycomb damping module (8).

3. The turbine last-stage blade according to claim 2, characterized in that, The honeycomb damping module (8) is tightly fitted with the mounting slot (7). The honeycomb damping module (8) includes a main body (80) adapted to the mounting slot (7). The main body (80) is provided with a honeycomb array, and the honeycomb array is filled with damping material (81) to dissipate the vibration energy of the blade.

4. The turbine last-stage blade according to claim 3, characterized in that, The positioning structure includes a positioning groove (10) formed on the opposite side wall of the mounting groove (7), and elastic claws (11) set on both sides of the main body (80) and engaged with the positioning groove (10).

5. A turbine last-stage blade according to claim 3 or 4, characterized in that, The positioning structure includes a positioning hole (13) at the bottom of the mounting groove (7) and a positioning pin (12) at the bottom of the main body (80) and inserted into the positioning pin (12), wherein the positioning pin (12) and the positioning hole (13) are interference fit.

6. The turbine last-stage blade according to claim 1, characterized in that, It also includes an anti-corrosion coating, which covers the transition fillet (9) surface, the outer surface of the honeycomb damping module (8), and the mating gap between the honeycomb damping module (8) and the mounting groove (7) to resist the impact of water droplets and media corrosion in a wet steam environment.

7. A turbine last-stage blade according to claim 6, characterized in that, The anti-corrosion coating is a TiAlN coating with a thickness of 0.3~0.5mm, a hardness ≥HRC65, and a bonding strength between the coating and the substrate ≥50MPa.

8. A method for manufacturing a steam turbine last-stage blade, used to manufacture the steam turbine last-stage blade according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Blade body preparation: First, 12Cr stainless steel or GH696 high temperature alloy forging blanks are selected as blanks. After the blanks are quenched and tempered, they are die-forged into an integrated structure of blade tip (1), blade body (2), transition section (4) and blade root (3). Then, the mounting groove (7) is machined on the non-load-bearing surface (6) of the transition section (4) by CNC milling, and the positioning groove (10) and positioning hole (13) are machined in the mounting groove (7). S2, manufacturing of honeycomb damping module (8): The module body containing elastic claws (11) and positioning pins (12) is formed by additive manufacturing technology. After the honeycomb array is processed in the module body, high temperature metal rubber damping material (81) is filled into the holes and then compacted and cured by vacuum pressure. S3, Module assembly; The honeycomb damping module (8) is embedded into the mounting slot (7), so that the elastic claw (11) is engaged in the positioning slot (10) and the positioning pin (12) is pressed into the positioning pin (12) hole, so that the module and the mounting slot (7) are tightly fixed. S4. Preparation of anti-corrosion coating: Using laser cladding technology, TiAlN coating is prepared on the outer surface of the blade transition fillet (9), the honeycomb damping module (8) and the mating gap after step S3, and the blade preparation is finally completed.

9. A method for preparing a turbine last-stage blade according to claim 8, characterized in that, In step S3, the cellular damping module (8) is first cooled by liquid nitrogen and then embedded in the mounting groove (7).

10. A method for preparing a steam turbine last-stage blade according to claim 8, characterized in that, In step S4, argon is used as the protective gas during the cladding process, and the coating is polished after it is formed.

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