A laser cladding repair method for turbine blade rim plate and fillet transition zone damage

Abstract

This invention relates to the field of aero-engine maintenance technology and discloses a laser cladding repair method for damage to the turbine blade rim and rounded corner transition area. The method involves: comprehensively inspecting the damaged areas of the turbine blade rim and rounded corner transition area using inspection equipment; treating the damaged areas of the turbine blade rim and rounded corner transition area using mechanical grinding; using the rounded corner vertex as the origin, and based on the length L of the right-angle side to be clad in the rounded corner transition area and the length L1 to be clad on the rim end face, the weld width W of a single cladding layer, and the height h of a single cladding layer, using an interpolation method to clad the areas of the rounded corner transition area and the rim end face; and finally, using a grinding equipment to finely repair the rim end face and rounded corner transition area. This invention solves the problems of large deformation of the rim end face and rounded corner transition area caused by traditional repair methods, and low bonding strength between the repair layer and the substrate, which cannot meet the assembly requirements of the rim and the usage requirements under high temperature and high vibration conditions.

Description

Technical Field

[0001] This invention relates to the field of aero-engine maintenance technology, and in particular to a laser cladding repair method for damage to turbine blade rim plates and fillet transition areas. Background Technology

[0002] Turbine blades are crucial for the efficient operation of aero engines and gas turbines. They are the core components of the unit that bear the largest load, are the most critical, and are widely used. Turbine blades must meet performance requirements such as resistance to static load and multi-cycle fatigue damage, resistance to high-temperature oxidation, and resistance to creep. At the same time, there are also corresponding specifications for aerodynamic efficiency. Therefore, the manufacturing of turbine blades is a complex engineering task involving metallurgy, process, and design.

[0003] The blade rim is a ring-shaped or square transition platform located at the bottom of the blade (i.e., the turbine blade) and above the blade root (i.e., the tenon). The bottom of the blade and the rim are connected by a rounded transition area. The main function of the rim is to form an independent airflow channel, block the high-temperature and high-pressure gas, prevent the gas from leaking between the blade root and the turbine disk, force the gas to do work only in the flow channel of the blade, protect the turbine disk, seals and other components that are not resistant to high temperatures, and the sides of the rims of adjacent blades contact each other to form frictional damping, which can suppress vibration and reduce the risk of fatigue fracture.

[0004] During long-term operation, the turbine blade rim plate is affected by centrifugal force, blade vibration, aerodynamic impact and high temperature oxidation. The mating surface of the rim plate end (i.e. rim plate end face) is prone to wear, resulting in excessive clearance with the turbine disk, causing vibration and noise. In addition, high temperature gas erosion can easily cause rim plate defects and failure of the rounded transition area. Furthermore, thermal stress concentration can easily cause microcracks. If not repaired in time, they will extend to the root of the tenon, leading to blade breakage.

[0005] However, current repair methods tend to cause large deformations in the end face and fillet transition area of ​​the flange, and the bonding strength between the repair layer and the substrate is low, which cannot meet the assembly requirements of the flange and the usage requirements under high temperature and high vibration conditions. Summary of the Invention

[0006] This application discloses a laser cladding repair method for damage to the blade rim and fillet transition area of ​​a turbine blade, in order to solve the problems in the prior art that easily lead to large deformation of the rim end face and fillet transition area, and low bonding strength between the repair layer and the substrate, which cannot meet the assembly requirements of the rim and the usage requirements under high temperature and high vibration conditions.

[0007] To solve the above problems, the present invention adopts the following technical solution: A laser cladding repair method for damage to the blade rim and fillet transition area of ​​a turbine blade includes the following steps: S1. Damage Detection and Parameter Marking: The damaged areas of the turbine blade edge plate and fillet transition zone are comprehensively inspected using detection equipment, and key parameters are recorded and marked. S2. Pretreatment: Mechanical grinding is used to treat the damaged areas of the turbine blade edge plate and the rounded corner transition area, and alcohol is used to clean the grinding area and the surrounding area. S3. Planning scheme for the cladding trajectory of the rounded corner transition zone: Taking the vertex of the rounded corner as the origin, based on the length L of the right-angled side that needs to be clad in the rounded corner transition zone, the width W of the weld bead of a single cladding layer and the height h of a single cladding layer, the laser cladding head uses the interpolation method to perform multi-layer cladding on the cladding area of ​​the rounded corner transition zone. S4. Cladding trajectory planning scheme for the end face of the rim plate: Based on the length L1 that needs to be clad on the end face of the rim plate, the weld width W of a single cladding layer and the height h of a single cladding layer, the laser cladding head uses the interpolation method to perform at least one cladding layer on the cladding area of ​​the end face of the rim plate. S5. Laser cladding: Using fiber laser cladding equipment, laser cladding is performed on the rounded corner transition area and the edge plate end face in sequence according to the cladding trajectory planning scheme of the rounded corner transition area and the cladding trajectory planning scheme of the edge plate end face; S6. Precision machining: The end face of the flange plate and the rounded transition area are precision machined using grinding equipment.

[0008] Further, in step S3, the part is rotated 45° so that the angle between the direction of the laser cladding head and the fillet is 45°, and the actual required cladding height is calculated geometrically as ( )L, Number of cladding layers N=( L÷h, N is rounded to the nearest integer; using the number of cladding layers N as the number of interpolation segments, points are selected within the length L of the right-angled side using the interpolation method to obtain two corresponding points, and interpolation is continued between the two points to obtain the number of cladding passes M required for each layer, M = distance between two points S÷(W-overlap width D), M is rounded to the nearest integer.

[0009] Furthermore, in step S4, the number of cladding passes m on the end face of the flange plate is m = L1 ÷ (W - overlap width D), and m is rounded to the nearest integer.

[0010] Furthermore, in step S4, the part is rotated 45° to reset, and the laser cladding head is deflected 10°-20° away from the part before cladding the edge plate end face, so that the cladding on the edge plate end face is tightly bonded to the cladding area of ​​the rounded corner transition zone.

[0011] Furthermore, in step S5, after the last layer of cladding in the rounded corner transition area and the end face of the edge plate is completed, only the laser power of the fiber laser cladding equipment is turned on, the powder feeding system is turned off, and the last layer in the rounded corner transition area and the end face of the edge plate is re-fused.

[0012] Furthermore, in step S5, the process parameters for laser cladding are as follows: laser power is 160-220W, scanning speed is 2-5mm / s, powder feeding rate is 4-6g / min, powder particle size is 20-250μm, and argon protection is 10-12L / min.

[0013] Furthermore, in step S5, when cladding the rounded corner transition area, the laser power of each cladding layer decreases by 10W from bottom to top.

[0014] Furthermore, in step S5, when cladding the rounded corner transition area, the laser cladding head needs to be raised by h after each layer is clad.

[0015] Furthermore, in step S3, with the vertex of the rounded corner as the origin, points 0 and 0′ are defined. With the length L of the right-angled side that needs to be clad in the rounded corner transition area, points Yx and Y′x are defined in the horizontal direction, and points Zx and Z′x are defined in the vertical direction. Combining the weld width W and the height h of the single-pass cladding layer, the laser cladding head uses interpolation to obtain other points.

[0016] Furthermore, in step S4, based on the length L1 that needs to be clad on the end face of the flange, four points A, a, B and b are defined in the horizontal direction. Combining the weld width W and the height h of the single cladding layer, the laser cladding head uses interpolation to obtain the other points.

[0017] The technical solution adopted in this invention can achieve the following beneficial effects: 1. This invention enables the laser cladding head to clad the rounded corner transition area and the edge plate end face in one go through the cladding trajectory planning scheme of the rounded corner transition area and the cladding trajectory planning scheme of the edge plate end face. This avoids incomplete fusion between the repair layer and the substrate, which leads to defects such as cracks. It solves the problems of large deformation of the edge plate end face and rounded corner transition area caused by traditional repair methods, and low bonding strength between the repair layer and the substrate, which cannot meet the assembly requirements of the edge plate and the usage requirements under high temperature and high vibration conditions. 2. This invention performs multi-layer cladding on the rounded corner transition area, with each layer widening to achieve a wider coverage area. This allows for a more precise fit to the concave surface of the rounded corner, avoiding the under-melting and over-melting issues that occur with traditional equal-width stacking at the edge of the concave surface. 3. This invention employs regional differentiated trajectory planning and interpolation cladding, and is compatible with both rounded concave surfaces and end-face planar structures, resulting in strong repair versatility and high forming precision. 4. This invention, through parameterized and standardized operation throughout the entire process, ensures strong controllability of repair quality and can effectively restore the structural strength, wear resistance, and fatigue resistance of the flange. 5. This invention combines laser cladding with refined pre-processing and post-processing, resulting in a low defect rate and minimal damage to the substrate. The repaired edge plate can meet the long-term service requirements under high temperature and high vibration conditions, reducing the replacement cost of parts. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of laser cladding repair of the rounded transition area and the edge plate end face disclosed in some embodiments of this application; Figure 2 This is a schematic diagram of the structure of the flange, turbine blade and tenon connection disclosed in some embodiments of this application.

[0020] In the picture: 10 - Edge plate; 11 - Edge plate end face; 20-Turbine blades; 30-Tenon; 40 - Rounded corner transition area. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] The terms "first," "second," "third," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," "third," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0023] The inventive concept of this application is described here: Turbine blades operate under varying temperatures and high-speed loads, facing intense aerodynamic friction and erosion from impurities such as sand and rainwater. The combined effects of static, dynamic, and cyclic loads can easily lead to fatigue cracks, thermal stress, and mechanical damage. Furthermore, the turbine blade rim is susceptible to wear at the end face due to centrifugal force, blade vibration, aerodynamic impact, and high-temperature oxidation. This wear can cause excessive clearance between the rim and the turbine disk, resulting in vibration and noise. High-temperature combustion gases can also cause rim defects and failure of the rounded transition zone. Concentrated thermal stress can also trigger microcracks, which, if not repaired promptly, can extend to the tenon root, leading to blade breakage.

[0024] Currently, the main repair methods for turbine blade rim plates and fillet transition areas include arc welding, brazing, and cold spraying. However, traditional arc welding involves a large heat input, which can easily lead to deformation at the rim plate ends and coarse grains, resulting in unstable repair layer performance and reduced high-temperature mechanical properties of the rim plate, failing to meet the requirements for use under high-temperature and high-vibration conditions. Brazing repair results in low bonding strength between the repair layer and the substrate, achieving only mechanical bonding and unable to withstand long-term vibration loads. Furthermore, the brazing process is prone to defects such as porosity and slag inclusions, leading to a short service life of the repaired rim plate, which is prone to failure again and cannot meet the assembly requirements of the rim plate. Although cold spraying repair results in small thermal deformation, the coating has low bonding strength with the substrate, making it difficult to withstand the load transfer requirements of the tenon.

[0025] Based on this, given the high dimensional accuracy requirements and strong material welding sensitivity of the gas turbine blade rim plate and rounded corner transition area, the inventors have provided a laser cladding repair method for turbine blade rim plate and rounded corner transition area damage that features low deformation, high strength, and high precision. This method addresses the problems caused by traditional repair methods, such as large deformation of the rim plate and rounded corner transition area, low bonding strength between the repair layer and the substrate, and inability to meet the assembly requirements of the rim plate and the usage requirements under high temperature and high vibration conditions.

[0026] The following is in conjunction with the appendix Figure 1 and Figure 2 This paper provides a detailed description of a laser cladding repair method for turbine blade 20 edge plate damage through specific embodiments and application scenarios.

[0027] Reference Figure 1 and Figure 2 A laser cladding repair method for damage to the blade rim and fillet transition area of ​​a turbine blade includes the following steps: S1. Damage Detection and Parameter Labeling: Refer to... Figure 2 The damaged areas of the turbine blade 20 edge plate 10 and the fillet transition area 40 were comprehensively inspected using testing equipment, and key parameters were recorded and marked. Specifically, the testing equipment can be X-ray inspection to detect internal microcracks in the damaged areas of the turbine blade 20, the flange 10, and the rounded transition zone 40. Key parameters recorded include, but are not limited to, crack location, crack length, flange 10 end thickness, damage depth, and damage width. The crack location and crack length are marked to provide data for subsequent trajectory planning, cladding layer thickness, and path design, thereby controlling the repair allowance from the source, reducing over-processing and material waste, and ensuring the dimensional accuracy of the repair.

[0028] S2, Preprocessing: Refer to... Figure 2 Mechanical grinding was used to treat the damaged areas of the turbine blade 20 edge plate 10 and the rounded transition area 40, removing cracks, surface oxide scale, fatigue spalling layer and defective substrate in the damaged area. Alcohol was used to clean the grinding area and the surrounding 50mm range to remove oil, dust and impurities. Specifically, by eliminating potential defects on the substrate surface, the bonding strength between the laser cladding powder and the substrate of the edge plate 10 and the rounded transition zone 40 is improved, effectively suppressing welding defects such as porosity, slag inclusions, and cracks during the cladding process, and improving the density of the repair layer.

[0029] S3, Cladding trajectory planning scheme for the rounded transition zone 40: Refer to Figure 1 and Figure 2 Taking the vertex of the rounded corner as the origin, based on the length L of the right-angled side that needs to be clad in the rounded corner transition area 40, the weld width W of the single cladding layer and the height h of the single cladding layer, the laser cladding head uses the interpolation method to perform multi-layer cladding on the cladding area of ​​the rounded corner transition area 40. Specifically, the included angle of the rounded corner transition area 40 is 90°; with the vertex of the rounded corner as the origin, its horizontal direction is the Y direction, and its vertical direction is the Z direction. The horizontal side of the rounded corner transition area 40 is connected to the end face 11 of the flange plate, and the vertical side of the rounded corner transition area 40 is connected to the bottom of the turbine blade 20. The bottom of the flange plate 10 is connected to the tenon 30. The horizontal and vertical sides have the same length L. The right-angle side L is the length of the rounded corner to be repaired, which is determined by the highest position of the crack in the Z direction detected in step S1. The weld width W and the height h of the single-pass cladding layer are measured by cladding the multi-pass layer on a flat plate. First, a cladding layer is welded on top, and then two more cladding layers are superimposed on this cladding layer. Then, the width and height of the cladding layer are measured to obtain the weld width W and the height h of a single cladding layer. Only one cladding layer is required. The structure of the laser cladding head is an existing structure, and its specific structure and working principle are common knowledge, so they will not be described in detail here. The interpolation method is used to adapt to the rounded concave surface structure, solving the problems of traditional straight cladding not being able to fit the curved surface, uneven cladding layer thickness, and poor rounded corner forming. Multi-layer cladding can release thermal stress layer by layer, reduce the risk of stress concentration at the rounded corners, ensure smooth rounded corner transition, and match the assembly and fitting accuracy of the flange 10.

[0030] Reference Figure 1 and Figure 2 In this embodiment, in step S3, points 0 and 0' are defined with the rounded corner vertex as the origin. Points Yx and Y'x are defined horizontally, and points Zx and Z'x are defined vertically, based on the length L of the right-angled side of the rounded corner transition zone 40 to be clad. Combining the weld width W and height h of the single-pass cladding layer, the laser cladding head uses interpolation to obtain the other points. (Where x is a positive integer.) Specifically, points 0 and 0′ are the two endpoints of the rounded corner vertex in the width direction of the rounded corner transition zone 40; points Yx and Y′x are defined at length L in the Y direction (these are the two endpoints in the width direction of the horizontal side of the rounded corner transition zone 40), and points Zx and Z′x are defined at length L in the Z direction (these are the two endpoints in the width direction of the vertical side of the rounded corner transition zone 40); that is, before cladding the rounded corner transition zone 40, points 0, 0′, Yx, Y′x, Zx, and Z′x need to be manually defined. These six positions are manual teaching points. By inputting the six points, the weld width W of a single cladding layer, and the height h of a single cladding layer into the program, the program calculates the offset of the laser cladding head using the interpolation formula. After the laser cladding head has clad one layer, it can automatically move to the position of the next cladding layer based on the offset, thus improving the cladding efficiency.

[0031] Reference Figure 1 and Figure 2 In this embodiment, points Y3 and Y′3 are defined at length L in the Y direction, and points Z3 and Z′3 are defined at length L in the Z direction. Based on the six teaching points (0, 0′, Y3, Y′3, Z3, and Z′3), combined with the weld width W and height h of the single-pass cladding layer, the laser cladding head uses interpolation to obtain points Y1, Y′1, Y2, Y′2, Z1, Z′1, Z2, and Z′2. This ensures that the laser cladding head's movement trajectory is continuous, smooth, and without abrupt changes, perfectly adapting to the structure of the rounded concave surface. The rounded transition area 40 on the other side of the part is defined in the same way.

[0032] Reference Figure 1 and Figure 2 In this embodiment, in step S3, the part is rotated 45° so that the angle between the direction of the laser cladding head and the fillet is 45°. The actual required cladding height is calculated geometrically as ( )L, Number of cladding layers N=( L÷h, N is rounded to the nearest integer; using the number of cladding layers N as the number of interpolation segments, points are selected within the length L of the right-angled side using the interpolation method to obtain two corresponding points, and interpolation is continued between the two points to obtain the number of cladding passes M required for each layer, M = distance between two points S÷(W-overlap width D), M is rounded to the nearest integer.

[0033] Specifically, the part is initially in a vertical position, and the laser cladding head is also vertically positioned. Initially, the direction of the laser cladding head is perpendicular to the Y direction of the rounded corner transition area 40. The part is positioned using a fixture. Before cladding the rounded corner transition area 40, the part is rotated 45° so that the angle between the direction of the laser cladding head and the rounded corner is 45°, unifying the laser incident angle and cladding posture, and aligning it with the rounded corner transition area 40. By precisely calculating the number of cladding layers N, the rounded corner repair allowance is quantitatively matched. This avoids insufficient layers leading to substandard repair dimensions, and also prevents excessive layers from causing excessive allowance and increased processing load. Multiple layers are precisely allocated to allocate the height of each layer, and the layers are stacked evenly, effectively releasing concentrated thermal stress at the rounded corner position, suppressing cracks and deformation, and ensuring uniform overall dimensions of the rounded corner. Using the number of cladding layers N as the interpolation segment number, points are selected within the length L of the Y and Z directions using the interpolation method to refine the cladding path nodes and obtain the corresponding two points. In this embodiment, the corresponding two points are Y1 and Z1 (i.e., Y′1 and Z′1), Y2 and Z2 (i.e., Y′2 and Z′2), and Y3 and Z3 (i.e., Y′3 and Z′3). The weld width W of a single cladding layer is equal to the overlap width D, which is equal to the offset of the laser cladding head. By converting the distance S between the two points with the offset of the laser cladding head, the number of cladding passes M of each layer is accurately determined, and the overlap of adjacent cladding layers is precisely controlled to avoid gaps and holes caused by too small an overlap, or local overheating and coarse structure caused by too large an overlap. This ensures that the cladding area of ​​each rounded corner is completely and seamlessly covered, eliminating local missing cladding and interlayer defects.

[0034] Reference Figure 1 and Figure 2 In this embodiment, the number of three cladding layers is obtained by interpolation. The first cladding layer has one cladding pass, denoted as 1-1. The second cladding layer has three cladding passes, denoted as 2-1, 2-2, and 2-3. The third cladding layer has five cladding passes, denoted as 3-1, 3-2, 3-3, 3-4, and 3-5. The cladding path of the laser cladding head is from 1-1 to 2-1, 2-2, 2-3, ... up to 3-5.

[0035] S4, Cladding trajectory planning scheme for edge plate end face 11: Refer to Figure 1 Based on the length L1 that needs to be clad on the end face 11 of the cladding plate, the weld width W of a single cladding layer and the height h of a single cladding layer, the laser cladding head uses the interpolation method to perform at least one layer of cladding on the cladding area of ​​the end face 11 of the cladding plate. Specifically, the length L1 = the total length of the flange plate 10 in the Y direction - the length L of the rounded transition area 40 in the Y direction; and the interpolation method is used to design a regular cladding path, and single or multiple layers of cladding are implemented according to the damage of the flange plate end face 11 to achieve uniform powder spreading and uniform cladding in the damaged area of ​​the flange plate end face 11, and ensure the flatness and dimensional consistency of the end face.

[0036] Reference Figure 1 and Figure 2 In this embodiment, in step S4, four points A, a, B and b are defined in the horizontal direction based on the length L1 that needs to be clad on the end face 11 of the flange plate. Combined with the weld width W and the height h of the single cladding layer, the laser cladding head uses interpolation to obtain the other points.

[0037] Specifically, points A and a (the two endpoints of the horizontal edge width of the flange 10) are defined at length L in the Y direction, which are the two ends of the contact point between the cladding path 3-5 and the flange end face 11; points B and b (the two endpoints of the horizontal edge width of the flange 10) are defined at the corners in the Y direction. That is, before cladding the flange end face 11, points A, a, B, and b need to be manually defined. These four positions are manual teaching points. By inputting the four points, the weld width W of a single cladding layer, and the height h of a single cladding layer into the program, the program calculates the offset of the laser cladding head using the interpolation formula. After the laser cladding head has clad one layer, it can automatically move to the position of the next cladding layer based on the offset, thus improving the cladding efficiency.

[0038] Reference Figure 1 and Figure 2 In this embodiment, points A and a (which coincide with points Y3 and Y′3) are defined at length L in the Y direction, and points B and b are defined at the corners in the Y direction. Based on these four teaching points (A, a, B, and b), and combined with the weld width W and height h of the single-pass cladding layer, the laser cladding head uses interpolation to obtain points A1, A′1, A2, A′2, A3, A′3, A4, and A′4. This ensures that the laser cladding head's movement trajectory is continuous, stable, and orderly, resulting in neatly arranged and uniformly overlapped welds on the end face, thus improving the overall flatness and structural density of the end face cladding layer. The edge plate end face 11 on the other side of the part is defined in the same way.

[0039] Reference Figure 1 and Figure 2 In this embodiment, the number of cladding layers is obtained by interpolation. The number of cladding passes is 1-1, 1-2, 1-3, 1-4, and 1-5. The cladding path of the laser cladding head is from 1-1 to 1-5.

[0040] In this embodiment, in step S4, the part is rotated 45° to reset, the laser cladding head is deflected 10°-20° away from the part, and then the edge plate end face 11 is clad so that the cladding of the edge plate end face 11 is tightly bonded to the cladding area of ​​the rounded corner transition area 40.

[0041] Specifically, before cladding the edge plate end face 11, the part is rotated 45° using a tooling to reset it, returning it to its initial state. This makes the angle between the laser cladding head and the vertical plane 10°-20°, optimizing the laser incident angle. This avoids the problems of concentrated light spots and severe local heat accumulation that exist in vertical cladding, strengthens the seamless connection between the edge plate end face 11 and the rounded corner cladding area, eliminates bonding defects, and improves the continuity and integrity of the overall repair layer. In this embodiment, the cladding area 3-5 of the rounded corner transition area 40 is combined with the cladding area 1-1 of the edge plate end face 11.

[0042] Reference Figure 1 and Figure 2 In this embodiment, in step S4, the number of cladding passes m on the edge plate end face 11 is m = L1 ÷ (W - overlap width D), and m is rounded to the nearest integer.

[0043] Specifically, the weld width W of a single cladding layer minus the overlap width D equals the offset of the laser cladding head. By converting the length L1 to be clad on the end face 11 of the flange plate into the offset of the laser cladding head, the number of cladding passes m for each layer is accurately determined. This precisely controls the overlap of adjacent cladding layers, avoiding gaps and holes caused by excessively small overlaps, or local overheating and coarse microstructure caused by excessively large overlaps. This ensures full coverage cladding of the end face, maintains the flatness of the end face and the consistency of the overall dimensions, reduces the subsequent finishing load, and improves repair efficiency.

[0044] S5, Laser Cladding: Refer to Figure 1 and Figure 2 The fiber laser cladding equipment is used to sequentially perform laser cladding on the rounded corner transition area 40 and the edge plate end face 11 according to the cladding trajectory planning scheme of the rounded corner transition area 40 and the cladding trajectory planning scheme of the edge plate end face 11. Specifically, the fiber laser cladding equipment is an existing device, which includes a laser cladding head. Its specific structure and working principle are common knowledge, so they will not be described in detail here. The fiber laser cladding equipment uses a wavelength of 1070nm, is equipped with a coaxial powder feeding system and a six-axis robotic arm, and uses high-temperature alloy powder that matches the substrate. First, laser cladding is performed on the rounded corner transition area 40, and then laser cladding is performed on the end face 11 of the edging plate.

[0045] In this embodiment, the process parameters for laser cladding in step S5 are as follows: laser power is 160-220W, scanning speed is 2-5mm / s, powder feeding rate is 4-6g / min, powder particle size is 20-250μm, and argon protection is 10-12L / min.

[0046] Specifically, the parameters are coupled and precisely adapted to the concave structure of the flange 10. The process features of partitioned cladding and multi-layer overlapping greatly improve the overall process stability and repeatability. Taking into account substrate protection, molding accuracy, microstructure density and mechanical properties, the repaired flange 10 and rounded transition area 40 can meet the stringent service requirements of high temperature, alternating load and friction wear, and extend the service life of the parts.

[0047] Reference Figure 1 and Figure 2 In this embodiment, during step S5, when cladding the rounded corner transition area 40, the laser power of each cladding layer decreases by 10W from bottom to top.

[0048] Specifically, refer to Figure 1 In this embodiment, during the first cladding layer, the laser power is 180-220W. The higher power of the first layer compared to the other layers helps to ensure metallurgical bonding with the substrate. During the second cladding layer, the laser power is 170-210W. Appropriately reducing the power can prevent excessive heat input to the parts and thus avoid defects. During the third cladding layer, the laser power is 160-200W. The cladding power is slightly lower than that of the second layer, which effectively ensures a strong bond between the cladding layers. Since a large amount of heat will remain in both the parts and the cladding layers after the first two layers are welded, maintaining a slightly lower power than the second layer avoids excessive power from generating cracks and pores on the surface of the cladding layer, effectively reducing residual stress in the rounded corner area and improving the overall strength of the repair structure.

[0049] Reference Figure 1 and Figure 2 In this embodiment, during step S5, when cladding the rounded corner transition area 40, the laser cladding head needs to be raised by h after each layer is clad. This can maintain the laser focal length, spot size, and powder convergence distance in the optimal range. It can also prevent focal length shift, spot divergence, and energy density reduction caused by multi-layer stacking, ensuring consistent melting effect for each layer and reducing defects.

[0050] Reference Figure 1 and Figure 2 In this embodiment, in step S5, after the last layer of cladding is completed in the rounded corner transition area 40 and the edge plate end face 11, only the laser power of the fiber laser cladding equipment is turned on, the powder feeding system is turned off, and the last layer of the rounded corner transition area 40 and the edge plate end face 11 is re-fused.

[0051] Specifically, the laser power of the fiber laser cladding equipment can be appropriately reduced; the remelting path is consistent with the path of the last layer of cladding; through remelting, the unmelted powder particles on the surface of the last layer can be melted and combined with the cladding layer, reducing surface roughness and allowing the gas that has not yet overflowed from the surface to diffuse out, reducing residual stress, improving the overall structural stability and service reliability after repair, and facilitating precise control of the outer dimensions and tolerances of the edge plate 10 and the rounded corner transition area 40, ensuring assembly accuracy.

[0052] S6. Precision machining: Refer to Figure 1 and Figure 2 The end face 11 of the flange plate and the rounded transition area 40 are finely repaired using grinding equipment.

[0053] Specifically, a five-axis CNC machine tool is used for fine repair. The machining path is set according to the original three-dimensional model. First, the end face 11 of the flange plate is ground, and then the rounded transition area 40 is ground. The dimensional deviation and surface roughness after laser cladding are corrected so that the dimensions, geometric tolerances and surface accuracy of the repaired flange plate 10 meet the assembly and use requirements, and the assembly fit and locking stability of the flange plate 10 are guaranteed.

[0054] In summary, this invention performs multi-layer cladding on the rounded corner transition area 40 through a cladding trajectory planning scheme, and cladding on the edge plate end face 11 through a cladding trajectory planning scheme. This allows the laser cladding head to clad both the rounded corner transition area 40 and the edge plate end face 11 in one go, avoiding incomplete fusion between the repair layer and the substrate, which can lead to defects such as cracks. This solves the problems of large deformation of the edge plate end face 11 and the rounded corner transition area 40 caused by traditional repair methods, as well as the low bonding strength between the repair layer and the substrate, which cannot meet the assembly requirements of the edge plate 10 and the usage requirements under high temperature and high vibration conditions. By manually providing teaching points and calculating the offset of the laser cladding head through a program, the laser cladding head moves according to the offset, reducing the time required for manual lifting of the gun and re-teaching points after each layer is clad, thus improving cladding efficiency.

[0055] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0056] Furthermore, it should be noted that the scope of the methods and apparatus in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser cladding repair method for damage to the blade rim and fillet transition area of ​​a turbine blade, characterized in that, Includes the following steps: S1. Damage Detection and Parameter Marking: The damaged areas of the turbine blade edge plate and fillet transition zone are comprehensively inspected using detection equipment, and key parameters are recorded and marked. S2. Pretreatment: Mechanical grinding is used to treat the damaged areas of the turbine blade edge plate and the rounded corner transition area, and alcohol is used to clean the grinding area and the surrounding area. S3. Planning scheme for the cladding trajectory of the rounded corner transition zone: Taking the vertex of the rounded corner as the origin, based on the length L of the right-angled side that needs to be clad in the rounded corner transition zone, the width W of the weld bead of a single cladding layer and the height h of a single cladding layer, the laser cladding head uses the interpolation method to perform multi-layer cladding on the cladding area of ​​the rounded corner transition zone. S4. Cladding trajectory planning scheme for the end face of the rim plate: Based on the length L1 that needs to be clad on the end face of the rim plate, the weld width W of a single cladding layer and the height h of a single cladding layer, the laser cladding head uses the interpolation method to perform at least one cladding layer on the cladding area of ​​the end face of the rim plate. S5. Laser cladding: Using fiber laser cladding equipment, laser cladding is performed on the rounded corner transition area and the edge plate end face in sequence according to the cladding trajectory planning scheme of the rounded corner transition area and the cladding trajectory planning scheme of the edge plate end face; S6. Precision machining: The end face of the flange plate and the rounded transition area are precision machined using grinding equipment.

2. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 1, characterized in that, In step S3, the part is rotated 45° so that the angle between the direction of the laser cladding head and the fillet is 45°. The actual required cladding height is calculated geometrically. )L, Number of cladding layers N=( L÷h, N is rounded to the nearest integer; using the number of cladding layers N as the number of interpolation segments, points are selected within the length L of the right-angled side using the interpolation method to obtain two corresponding points, and interpolation is continued between the two points to obtain the number of cladding passes M required for each layer, M = distance between two points S÷(W-overlap width D), M is rounded to the nearest integer.

3. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 2, characterized in that, In step S4, the number of cladding passes m on the end face of the edge plate is m = L1 ÷ (W - overlap width D), and m is rounded to the nearest integer.

4. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 3, characterized in that, In step S4, the part is rotated 45° to reset, the laser cladding head is deflected 10°-20° away from the part, and then the edge plate end face is clad to ensure that the cladding on the edge plate end face is tightly bonded to the cladding area of ​​the rounded corner transition zone.

5. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 1, characterized in that, In step S5, after the last layer of cladding in the rounded corner transition area and the end face of the edge plate is completed, only the laser power of the fiber laser cladding equipment is turned on, the powder feeding system is turned off, and the last layer in the rounded corner transition area and the end face of the edge plate is remelted.

6. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 2, characterized in that, In step S5, the laser cladding process parameters are as follows: laser power is 160-220W, scanning speed is 2-5mm / s, powder feeding rate is 4-6g / min, powder particle size is 20-250μm, and argon protection is 10-12L / min.

7. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 6, characterized in that, In step S5, when cladding the rounded corner transition area, the laser power of each cladding layer decreases by 10W from bottom to top.

8. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 6, characterized in that, In step S5, when cladding the rounded corner transition area, the laser cladding head needs to be raised by h after each layer is clad.

9. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 2, characterized in that, In step S3, with the vertex of the rounded corner as the origin, points 0 and 0′ are defined. With the length L of the right-angled side that needs to be clad in the rounded corner transition area, points Yx and Y′x are defined in the horizontal direction, and points Zx and Z′x are defined in the vertical direction. Combining the weld width W and the height h of the single-pass cladding layer, the laser cladding head uses interpolation to obtain other points.

10. The laser cladding repair method for damage to the turbine blade rim and fillet transition area according to claim 3, characterized in that, In step S4, four points A, a, B and b are defined in the horizontal direction based on the length L1 that needs to be clad on the end face of the flange. Combining the weld width W and the height h of the single cladding layer, the laser cladding head uses interpolation to obtain the other points.

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