Laser cladding repair method for aero-engine blade tip

Abstract

This invention provides a laser cladding repair method for the tip of an aero-engine blade. By optimizing the laser cladding process parameters and combining them with a specific scanning path, the problem of heat accumulation during the repair of the blade tip by laser cladding is solved. This method allows for a more holistic and systematic repair of the blade tip, ensuring that the quality of the repaired blade meets the requirements. It also improves the blade repair efficiency, thereby increasing the utilization rate of the failed blade and reducing the blade manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of laser cladding repair technology, and more specifically to a laser cladding repair method for the tip of an aero-engine blade. Background Technology

[0002] Currently, aero-engine blades are commonly made from titanium alloys, nickel-based alloys, and stainless steel, and are formed using precision investment casting. Therefore, damaged aero-engine blades are difficult to repair and are usually replaced by purchasing new blades, resulting in enormous costs.

[0003] Laser cladding technology is an advanced manufacturing technology that combines laser technology with additive manufacturing technology. As an advanced manufacturing and processing technology, it is widely used in material surface modification, metal 3D printing, and repair of failed parts. By using laser cladding technology to stack and repair aero-engine blades, costs can be greatly reduced.

[0004] However, in the process of repairing aero-engine blades using laser cladding technology, the narrow blade tip is prone to heat accumulation and spheroidization. Furthermore, severe heat accumulation can cause the blade tip to collapse, making it difficult to shape the repaired blade and resulting in significant defects. Summary of the Invention

[0005] The purpose of this invention is to address the problem that the tips of aero-engine blades tend to collapse during existing laser cladding repairs, making it impossible to repair and reshape the blades. This invention provides a laser cladding repair method for aero-engine blade tips, which effectively repairs failed blades and enables the reuse of scrap materials by optimizing the laser cladding process.

[0006] According to the purpose of this invention, a laser cladding repair method for the tip of an aero-engine blade is provided, comprising the following steps:

[0007] S1. Using the required alloy powder as raw material, print the corresponding single-pass cladding layer on the substrate using multiple sets of laser cladding process parameters. Determine the required laser cladding process parameters based on the desired surface morphology and internal structure of the cladding layer, as well as the width-to-thickness ratio of the single-pass cladding layer to be overlapped.

[0008] S2. Using the molten channel height determined in step S1 as the initial cladding lift, the laser cladding process parameters determined in step S1 and the alloy powder used in step S1 are used to print the wall layer by layer on the substrate in a single pass. The cladding lift is adjusted according to the required wall shape until the wall shape requirements are met. The corresponding cladding lift is the required cladding lift.

[0009] S3. Using the parameters determined in steps S1 and S2, and the alloy powder used in step S1, a block is printed on the substrate layer by layer in multiple passes. The overlap rate between the required single-pass cladding layers is determined according to the desired surface morphology and internal structure of the block.

[0010] S4. Using laser cladding technology, with the parameters determined in steps S1, S2 and S3 as the printed parameters, the alloy powder used in step S1 is used to print the repair layer by layer on the tip of the aero-engine blade to be repaired until the repair of the aero-engine blade tip is completed.

[0011] The printing path includes: starting from the tip of the aero-engine blade, printing the outer contour according to the shape of the blade tip until the outer contour is closed, and the printing end point does not overlap with the printing start point, and the area enclosed by the outer contour is defined as the filling area.

[0012] Then, the filling area is printed in a single-pass cladding layer overlapping manner until the filling area is completely filled. The printing direction of the filling areas of adjacent printing layers is set to be orthogonal.

[0013] As an optional implementation, when printing the filling area, the printing start point is the end furthest from the leaf tip.

[0014] As an optional implementation, the printing directions of the filling regions of adjacent printing layers are set to be orthogonal, including:

[0015] A rectangular coordinate system is established with the tip of the leaf as the origin. One of the adjacent printing layers is defined as the first printing layer, and the other printing layer is defined as the second printing layer.

[0016] When printing the filling area of ​​the first printing layer, the single-pass cladding layer is printed along the Y-axis direction and overlapped one by one along the X-axis direction;

[0017] When printing the filling area of ​​the second printing layer, the single-pass cladding layer is printed along the X-axis direction and overlapped one by one along the Y-axis direction.

[0018] As an optional implementation, when printing the filling area of ​​the first printing layer, if the area to be printed is smaller than the laser spot area, the printing direction is changed, and the current printing parameters are used to fill the remaining part completely in a single-pass cladding direct forming method.

[0019] As an optional implementation, the required laser cladding process parameters determined in step S1 are: laser power 430w, scanning speed 5mm / s, defocusing amount -2mm, powder tray rotation speed 3, powder carrier gas flow rate 2, cladding width 1.25mm, and cladding thickness 0.44mm.

[0020] As an optional implementation, in step S2, the required cladding lift is controlled between 85% and 95% of the thickness of a single cladding layer.

[0021] As an optional implementation, in step S3, the overlap rate between the required single cladding layers is determined to be between 15% and 26%.

[0022] As an optional implementation, in step S1, the desired surface morphology and internal structure of the cladding layer are as follows: the surface morphology of the cladding layer is smooth and the internal structure is free of defects; the width-to-thickness ratio of the single cladding layer required for overlap is 3:1.

[0023] In step S2, the required shape of the wall is that the wall surface is flat;

[0024] Step S3, the desired standard for the surface morphology and internal structure of the block is: the surface morphology of the block is smooth and the internal structure is free of defects.

[0025] As an optional implementation, the printing interval between adjacent printing layers is 30 seconds.

[0026] As an optional implementation, the required alloy material is a nickel-based alloy.

[0027] As can be seen from the above technical solutions of the present invention, the laser cladding repair method for aero-engine blade tips proposed in this invention solves the problem of heat accumulation in the repair of laser cladding blade tips by optimizing the process parameters of laser cladding and combining them with a specific scanning path. It can perform blade tip repair in a more holistic and systematic way, and the quality of the repaired blade meets the requirements. At the same time, it improves the blade repair efficiency, thereby increasing the utilization rate of failed blades and reducing blade manufacturing costs.

[0028] The laser cladding repair method for aero-engine blade tips of the present invention has the advantages of fast repair speed, accurate repair size, easy automation control, small thermal impact on the substrate, fine and uniform repair structure and good metallurgical bonding with the substrate. It can be used to solve the problem of repairing cracks in aero-engine blades, and has broad application prospects in the repair of cracks in other equipment components.

[0029] The laser cladding repair method for the tips of aero-engine blades of the present invention has strong adaptability to the repair of different types of blades and can be applied to the repair and shaping of blades of other materials and different types. Attached Figure Description

[0030] Figure 1 This is a process flow diagram of the laser cladding repair method for the tip of an aero-engine blade according to the present invention.

[0031] Figure 2 This is an example image of a single-pass cladding layer printed according to the present invention.

[0032] Figure 3 This is an example of a printed wall according to the present invention.

[0033] Figure 4 This is a physical image of a printed block exemplified by the present invention.

[0034] Figure 5 This is a schematic diagram of the printing path of the first printing layer of the present invention; wherein, the blue line is the printing path, the green line is the idle path when the laser head does not emit light, and the red line is the printing path of single-pass cladding direct forming.

[0035] Figure 6 This is a schematic diagram of the printing path of the second printing layer of the present invention; wherein, the blue line is the printing path and the green line is the idle path of the laser head when no light is emitted.

[0036] Figure 7 This is a physical image showing the results of a single-pass cladding experiment in Embodiment 1 of the present invention.

[0037] Figure 8 This is a physical image showing the results of the wall cladding experiment in Embodiment 1 of the present invention.

[0038] Figure 9 This is a physical image showing the results of the block cladding experiment in Embodiment 1 of the present invention.

[0039] Figure 10 This is a physical image of the first printing layer in Embodiment 1 of the present invention.

[0040] Figure 11 This is a physical image of the second printing layer in Embodiment 1 of the present invention.

[0041] Figure 12 This is a physical image of the repaired object in Embodiment 1 of the present invention.

[0042] Figure 13 This is a physical image of the single-layer structure repaired in Comparative Example 1 of this invention. Detailed Implementation

[0043] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0044] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, in which numerous illustrative embodiments are shown. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described below in more detail, can be implemented in any of a number of ways.

[0045] IN-625 alloy is a solid solution strengthened nickel-based wrought superalloy with molybdenum and niobium as the main strengthening elements. It has excellent corrosion resistance and oxidation resistance, good tensile and fatigue properties from low temperature to 980℃, and is resistant to stress corrosion under salt spray atmosphere. Therefore, it can be widely used in the manufacture of aero-engine parts, aerospace structural components, and chemical equipment.

[0046] In the repair of aero-engine blades using laser cladding, reducing heat accumulation and collapse at both ends of the blade tip, and ensuring that the repaired blades have a reasonable surface morphology and good internal structure are key issues that need to be addressed in the blade repair process. At the same time, it is necessary to construct a complete and feasible process route to achieve small-batch production of scrapped blades.

[0047] Therefore, this invention constructs a method specifically for repairing blade tips, which can repair blade tips in a more holistic and systematic way, solve the problem of blade tips collapsing due to heat accumulation, improve repair quality and efficiency, and realize small-batch production of scrapped blades.

[0048] Combination Figure 1-5 As shown, in an exemplary embodiment of the present invention, a method for laser cladding repair of the tip of an aero-engine blade is provided, comprising the following steps:

[0049] S1, such as Figure 2 As shown, using nickel-based alloy powder as raw material, multiple sets of laser cladding process parameters are used to print corresponding single-pass cladding layers on the substrate. The required laser cladding process parameters are determined based on the desired surface morphology and internal structure of the cladding layer, as well as the width-to-thickness ratio of the single-pass cladding layer required for overlapping.

[0050] S2, such as Figure 3 As shown, the thickness of the single-pass cladding layer determined in step S1 is used as the initial cladding lift. The parameters determined in step S1 are used, and the nickel-based alloy is printed layer by layer on the substrate to obtain the wall. The cladding lift is adjusted according to the required wall morphology until the wall morphology requirements are met. The corresponding cladding lift is the required cladding lift.

[0051] S3, such as Figure 4 As shown, using the parameters determined in steps S1 and S2, a block is obtained by multi-pass layer-by-layer printing on a substrate using a nickel-based alloy. The required overlap rate between single-pass cladding layers is determined based on the desired surface morphology and internal structure of the block.

[0052] S4. Using laser cladding technology, with the parameters determined in steps S1, S2 and S3 as the printed parameters, nickel-based alloy is used to print the repair layer by layer on the tip of the aero-engine blade to be repaired until the repair of the aero-engine blade tip is completed.

[0053] The printing path includes: starting from the tip of the aero-engine blade, printing the outer contour according to the shape of the blade tip until the outer contour is closed, and the printing end point does not overlap with the printing start point, and the area enclosed by the outer contour is defined as the filling area.

[0054] Understandable, combined Figure 5 As shown, the outer contour is printed until the entire outer contour is closed, that is, the printing endpoint (point b) is near the tip and overlaps with the already formed part, but the printing endpoint (point b) does not coincide with the printing start point (point a).

[0055] Then, the filling area is printed in a single-pass cladding layer overlapping manner until the filling area is completely filled. The printing direction of the filling areas of adjacent printing layers is set to orthogonal.

[0056] As an optional implementation, when printing the filling area, the printing start point is the end furthest from the tip of the leaf.

[0057] Combination Figure 5-6 As shown, in an optional implementation, the printing directions of the filling areas of adjacent printing layers are set to be orthogonal, including:

[0058] A rectangular coordinate system is established with the tip of the leaf as the origin. One of the adjacent printing layers is defined as the first printing layer, and the other printing layer is defined as the second printing layer.

[0059] like Figure 5 As shown, when printing the filling area of ​​the first printing layer, the single-pass cladding layer is printed along the Y-axis direction and overlapped one by one along the X-axis direction.

[0060] like Figure 6 As shown, when printing the filling area of ​​the second printing layer, the single-pass cladding layer is printed along the X-axis direction and overlapped one by one along the Y-axis direction.

[0061] As an optional implementation, when the first printing layer is placed in the filling area for printing, if the area to be printed is smaller than the laser spot area, the printing direction is changed, and the current printing parameters are used to fill the remaining part completely in a single-pass cladding direct forming method.

[0062] Understandable, such as Figure 5As shown, when printing and filling the filling area of ​​the first printing layer, the single-pass cladding layer is printed along the Y-axis and overlapped one by one along the X-axis. When the printing and filling is close to the tip of the blade, the area to be printed and filled is too small (within the red box), which is smaller than the area of ​​the laser spot and cannot be effectively filled. Therefore, the printing reverse is changed, and the current printing parameters are used to print the single-pass cladding layer (red line) along the X-axis. That is, the remaining part is completely filled by direct forming with single-pass cladding.

[0063] As an optional implementation, the parameters used in the single-pass cladding test in step S1 can be selected according to the actual situation. For example, three parameters can be selected, and three factors can be selected for each parameter to conduct an orthogonal experiment. Alternatively, some parameters can be determined according to the actual situation, and the range of other parameters can be expanded by referring to commonly used values. Different values ​​can be selected to design corresponding groups for single-pass cladding tests, observe the morphology of each group of single-pass cladding layers, and select the optimal laser cladding process parameters in combination with the aspect ratio required for overlapping.

[0064] As an optional implementation, the required laser cladding process parameters determined in step S1 are: laser power 430w, scanning speed 5mm / s, defocusing amount -2mm, powder tray rotation speed 3, powder carrier gas flow rate 2, cladding width 1.25mm, and cladding height 0.44mm.

[0065] As an optional implementation, the initial cladding lift is the thickness of the single cladding layer determined in step S1. Based on the initial cladding lift, multiple cladding lifts are selected. The selected cladding lift and the parameters determined in step S1 are used to print the corresponding wall on the substrate. The flatness of the wall shape is used as the standard to determine the cladding lift that meets the requirements.

[0066] As an optional implementation, in step S2, the required cladding lift is controlled between 85% and 95% of the thickness of a single cladding layer. At this time, the shape of the wall is flat and the defocusing amount remains unchanged, which meets the requirements. In particular, it is preferred to be 93% of the thickness of a single cladding layer, that is, the optimal cladding lift is designed to be 0.41mm.

[0067] As an optional implementation, in step S3, the overlap rate between the required single-pass cladding layers is determined to be between 15% and 26%. This is achieved by changing the maximum and minimum step distances between adjacent single passes. When the overlap rate is less than 15%, the clad block will have large grooves, large defects, and an irregular surface morphology. When the overlap rate is greater than 26%, the clad block will be mountain-shaped, with severe heat accumulation in the middle of the block and the height at both ends being lower than the height in the middle. Therefore, when the overlap rate is between 15% and 26%, the surface morphology is smooth and there are no defects.

[0068] As an optional implementation, in step S1, the desired surface morphology and internal structure of the cladding layer are: the surface morphology of the cladding layer is smooth and the internal structure is free of defects.

[0069] The width-to-thickness ratio of the single cladding layer required for overlapping is 3:1. In practice, this ratio can fluctuate slightly. If it exceeds this range, it will have a significant impact on the subsequent exploration of cladding improvement and cladding overlap rate. If the width is much greater than the thickness, thermal accumulation and collapse defects are likely to occur. If the thickness is too large, gaps are very likely to occur when overlapping later.

[0070] In step S2, the required shape of the wall is that the wall surface is flat, that is, the wall does not appear wavy when observed from various angles, and the whole is straight, flat and without defects.

[0071] Step S3, the desired standard for the surface morphology and internal structure of the block is: the surface morphology of the block is smooth and the internal structure is free of defects.

[0072] As an optional implementation, the printing interval between adjacent printing layers is 30 seconds.

[0073] As an optional implementation, the required alloy material is a nickel-based alloy, such as IN-625.

[0074] To facilitate better understanding, the present invention will be further illustrated below with several specific examples, but the preparation process is not limited to these examples, and the content of the present invention is not limited to these examples.

[0075] Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0076] Example 1

[0077] (1) Single-pass cladding experiment to determine suitable single pass and morphology

[0078] Using commercially available IN-625 alloy powder as raw material, multiple sets of single-pass cladding layers were printed according to the parameters in Table 1. The results are as follows: Figure 7 As shown, observe the morphology of each group of single-layer cladding after printing. Combined with the necessary aspect ratio during overlap, the parameters of the corresponding group that meet the requirements of flat morphology, no internal defects, and aspect ratio of about 3:1 are satisfied.

[0079] Table 1

[0080] Group Defocusing amount Z / mm powder tray speed Powder-carrying gas flow rate Power P / W Scanning speed V / mm / s Melt run width W / mm Melt run height H / mm 1-1 -2 3 2 310 5 1.14 0.39 1-2 -2 3 2 340 5 1.15 0.42 1-3 -2 3 2 370 5 1.14 0.44 1-4 -2 3 2 400 5 1.20 0.45 1-5 -2 3 2 430 5 1.25 0.44 1-6 -2 3 2 460 5 1.28 0.46 1-7 -2 3 2 490 5 1.30 0.47 1-8 -2 3 2 520 5 1.34 0.49 1-9 -2 3 2 550 5 1.45 0.47 1-10 -2 3 2 580 5 1.46 0.50

[0081] The optimal process parameters are groups 1-5. The final determined process parameters are: laser power 430w, scanning speed 5mm / s, defocusing amount -2mm, powder tray speed 3, powder carrier gas flow rate 2, melt channel width 1.25, and melt channel thickness 0.44.

[0082] (2) The wall cladding experiment finally determined the lifting amount of the cladding layer.

[0083] Using the parameters from step (1), with an initial cladding layer increase of 0.44, a set of data was designed, and the corresponding wall was printed. The wall was obtained by printing 20 layers continuously in a single pass. The corresponding data for each set is shown in Table 2, and the results are as follows. Figure 8 As shown, the cladding lift is controlled between 85% and 95% of the thickness of a single cladding layer. At this point, the wall has a smooth shape and the decoking amount remains unchanged, which meets the requirements.

[0084] Table 2

[0085] Group Defocusing amount Z / mm powder tray speed Powder-carrying gas flow rate Power P / W Scanning speed V / mm / s Melt run width W / mm Melt run height H / mm Lifting amount (mm) 2-1 -2 3 2 430 5 1.25 0.44 0.35 2-2 -2 3 2 430 5 1.25 0.44 0.37 2-3 -2 3 2 430 5 1.25 0.44 0.39 2-4 -2 3 2 430 5 1.25 0.44 0.41 2-5 -2 3 2 430 5 1.25 0.44 0.43 2-6 -2 3 2 430 5 1.25 0.44 0.45 2-7 -2 3 2 430 5 1.25 0.44 0.47 2-8 -2 3 2 430 5 1.25 0.44 0.49 2-9 -2 3 2 430 5 1.25 0.44 0.48 2-10 -2 3 2 430 5 1.25 0.44 0.50

[0086] The optimal cladding lift is 93% of the thickness, meaning the optimal cladding lift is designed to be 0.41mm.

[0087] (3) Block cladding molding experiment to determine the direct overlap rate between single passes.

[0088] Using the parameters from steps (1) and (2), a block (length × width × height = 70 × 20 × 10 mm) was printed. The overlap was achieved by changing the maximum and minimum step distance between adjacent single tracks. The experimental groups were set as shown in Table 3, and the results were as follows: Figure 9 As shown, the overlap rate is between 15% and 26%, the surface morphology is smooth, and there are no defects.

[0089] Table 3

[0090] Group Defocusing amount Z / mm powder tray speed Powder-carrying gas flow rate Power P / W Scanning speed V / mm / s Melt run width W / mm Melt run height H / mm Lifting amount (mm) Overlap rate 3-1 -2 3 2 430 5 1.25 0.44 0.41 35% 3-2 -2 3 2 430 5 1.25 0.44 0.41 30% 3-3 -2 3 2 430 5 1.25 0.44 0.41 26% 3-4 -2 3 2 430 5 1.25 0.44 0.41 16% 3-5 -2 3 2 430 5 1.25 0.44 0.41 15%

[0091] An overlap rate of 16% is optimal, resulting in a smooth surface with no defects, thus meeting the requirements.

[0092] (4) Use UG for preliminary programming. Import the data determined in steps (1), (2) and (3) into the UG programming path software and set the path as follows:

[0093] Starting from the tip of the aero-engine blade, the outer contour is printed according to the shape of the blade tip until the outer contour is closed and the printing end point does not overlap with the printing start point. The area enclosed by the outer contour is defined as the filling area.

[0094] A rectangular coordinate system is established with the tip of the leaf as the origin. One of the adjacent printing layers is defined as the first printing layer, and the other printing layer is defined as the second printing layer.

[0095] When printing and filling the filling area of ​​the first printing layer, the single-pass cladding layer is printed along the Y-axis and overlapped one by one along the X-axis. When it is close to the tip of the blade, and the laser head can no longer follow the set path, the direction is changed to the X-axis, and the single-pass cladding layer is printed directly to form the filling using the current parameters; the result is as follows. Figure 10 As shown, no collapse will occur during the repair process, and the surface morphology will be smooth.

[0096] When printing and filling the filling area of ​​the second printing layer, single-pass cladding layers are printed along the X-axis and overlapped one by one along the Y-axis; the result is as follows. Figure 11 As shown, no collapse will occur during the repair process, and the surface morphology will be smooth.

[0097] The repair is completed by printing the first and second printing layers alternately on the tip of the aero-engine blade to be repaired. After printing each layer, the process is paused for 30 seconds before printing the next layer. After printing 20 layers, the repair is completed.

[0098] Repair results as follows Figure 12 As shown, by using cross-printing of two paths, the surface morphology is ensured to be flat when stacking layers, with fewer internal defects, and no collapse will occur during repair. The blade tip can be repaired by laser cladding.

[0099] Comparative Example 1

[0100] Using the data determined in Example 1, preliminary programming was performed using UG. The data determined in (1), (2) and (3) of Example 1 were imported into the UG programming path software, and the path was set as follows:

[0101] Starting from the tip of the aero-engine blade, the outer contour is printed according to the shape of the blade tip until the outer contour is closed and the printing end point overlaps with the printing start point. The area enclosed by the outer contour is defined as the filling area.

[0102] A rectangular coordinate system is established with the tip of the leaf as the origin. When printing and filling the area, a "bow"-shaped scanning path is used, starting from a point far from the tip of the leaf and moving towards the tip.

[0103] Repaired single-layer printing, such as Figure 13 As shown in the figure, it can be seen that the area near the endpoint cannot be clad, resulting in a large defect. Due to the bow-shaped cutting tool, the thickness of the inner filling is higher than the thickness of the outer contour. When stacking layers, the thickness of the outer contour will be much lower than the thickness of the inner filling, causing the outer contour to collapse and making laser cladding repair impossible.

[0104] In summary, the method of the present invention can repair blade tips in a more holistic and systematic way, solve the problem of blade tip collapse caused by heat accumulation, improve repair quality and efficiency, and realize small-batch production of scrapped blades.

[0105] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for laser cladding repair of aero-engine blade tips, characterized in that, Includes the following steps: S1. Using the required alloy powder as raw material, print the corresponding single-pass cladding layer on the substrate using multiple sets of laser cladding process parameters. Determine the required laser cladding process parameters based on the desired surface morphology and internal structure of the cladding layer, as well as the width-to-thickness ratio of the single-pass cladding layer to be overlapped. S2. Using the molten channel height determined in step S1 as the initial cladding lift, the laser cladding process parameters determined in step S1 and the alloy powder used in step S1 are used to print the wall layer by layer on the substrate in a single pass. The cladding lift is adjusted according to the required wall shape until the wall shape requirements are met. The corresponding cladding lift is the required cladding lift. S3. Using the parameters determined in steps S1 and S2, and the alloy powder used in step S1, a block is printed on the substrate layer by layer in multiple passes. The overlap rate between the required single-pass cladding layers is determined according to the desired surface morphology and internal structure of the block. S4. Using laser cladding technology, with the parameters determined in steps S1, S2 and S3 as the printed parameters, the alloy powder used in step S1 is used to print the repair layer by layer on the tip of the aero-engine blade to be repaired until the repair of the aero-engine blade tip is completed. The printing path includes: starting from the tip of the aero-engine blade, printing the outer contour according to the shape of the blade tip until the outer contour is closed, and the printing end point does not overlap with the printing start point, and the area enclosed by the outer contour is defined as the filling area. Then, the filling area is printed using a single-pass cladding layer overlapping method until the filling area is completely filled. When printing the filling area, the printing start point is the end furthest from the blade tip. The printing directions of the filling areas of adjacent printing layers are set to be orthogonal, specifically including: A rectangular coordinate system is established with the tip of the leaf tip as the origin. One of the adjacent printing layers is defined as the first printing layer, and the other printing layer is defined as the second printing layer. When printing the filling area of ​​the first printing layer, the single-pass cladding layer is printed along the Y-axis direction and overlapped one by one along the X-axis direction; and when the area to be printed is smaller than the laser spot area, the printing direction is changed, and the current printing parameters are used to fill the remaining part completely by single-pass cladding direct forming. When printing the filling area of ​​the second printing layer, the single-pass cladding layer is printed along the X-axis direction and overlapped one by one along the Y-axis direction.

2. The laser cladding repair method for the tip of an aero-engine blade according to claim 1, characterized in that, In step S1, the required laser cladding process parameters are determined as follows: laser power 430w, scanning speed 5mm / s, defocusing amount -2mm, cladding width 1.25mm, and cladding thickness 0.44mm.

3. The laser cladding repair method for the tip of an aero-engine blade according to claim 1, characterized in that, In step S2, the required cladding lift is controlled between 85% and 95% of the thickness of a single cladding layer.

4. The laser cladding repair method for the tip of an aero-engine blade according to claim 1, characterized in that, In step S3, the overlap rate between the required single cladding layers is determined to be between 15% and 26%.

5. The laser cladding repair method for the tip of an aero-engine blade according to claim 1, characterized in that, Step S1, the desired surface morphology and internal structure of the cladding layer are as follows: the surface morphology of the cladding layer is smooth and the internal structure is free of defects; the width-to-thickness ratio of the single cladding layer required for overlap is 3:

1. In step S2, the required shape of the wall is that the wall surface is flat; Step S3, the desired standard for the surface morphology and internal structure of the block is: the surface morphology of the block is smooth and the internal structure is free of defects.

6. The laser cladding repair method for the tip of an aero-engine blade according to claim 1, characterized in that, The printing interval between adjacent printing layers is 30 seconds.

7. The laser cladding repair method for the tip of an aero-engine blade according to any one of claims 1-6, characterized in that, The required alloy powder is a nickel-based alloy powder.

Images