A method for high-speed laser cladding additive repair of 1Cr11Ni2W2MoV stainless steel gear shafts for aerospace applications.

Abstract

This invention relates to the field of laser cladding additive repair technology for martensitic stainless steel gear shafts, specifically a method for high-speed laser cladding additive repair of aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts. The method includes: removing the oxide film from the outer surface of the gear shaft, grinding and cleaning the damaged area, determining the high-speed laser cladding parameters, then performing cladding repair on the damaged gear shaft, stress-relief annealing on the gear shaft after repair, and finally restoring the gear shaft to its original dimensions using machining methods, thus completing the repair. This invention provides a method for high-speed laser cladding additive repair of aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts, enabling high-quality repair of damaged 1Cr11Ni2W2MoV stainless steel gear shafts, facilitating repair work for testing and operators, and providing theoretical guidance and practical repair cases for the repair of related components and accessories.

Description

Technical Field

[0001] This invention relates to the field of laser cladding additive repair technology for martensitic stainless steel gear shafts, specifically a method for high-speed laser cladding additive repair of 1Cr11Ni2W2MoV stainless steel gear shafts used in aviation. Background Technology

[0002] 1Cr11Ni2W2MoV martensitic heat-resistant stainless steel possesses excellent strength and toughness, as well as good machinability, and is widely used in the manufacture of gears and other components in pump devices of aircraft fuel and cooling systems. During the operation of various aircraft systems, gears rotate at extremely high speeds, and these gears are positioned and fixed within the system via gear shafts. During use, mechanical vibration and scratches can cause uneven wear and scratches on the outer surface of the gear shafts, requiring restoration of their dimensional and morphological properties during aircraft overhauls. However, due to the high cost of aircraft gears, replacing damaged parts increases maintenance costs. Furthermore, 1Cr11Ni2W2MoV stainless steel is highly sensitive to heat input, and conventional repair methods result in large heat-affected zones, leading to performance degradation. Therefore, a low-cost, high-quality repair method suitable for 1Cr11Ni2W2MoV gear shafts is needed.

[0003] High-speed laser cladding repair technology is a novel repair method developed in recent years. This technology optimizes the coupling efficiency of laser and powder, enabling the powder to melt during flight and repairing damaged parts simultaneously with the micro-melting of the substrate. Because more energy is used to melt the powder during the repair process, the heat input to the substrate is lower, resulting in less thermal damage to the substrate and achieving low-thermal-damage repair of damaged parts. 1Cr11Ni2W2MoV, as a martensitic heat-resistant stainless steel, differs from other materials in composition, microstructure, form, and properties. Therefore, research is needed on high-speed laser cladding repair of this material to guide the repair of corresponding parts and accessories in actual production. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for high-speed laser cladding additive repair of 1Cr11Ni2W2MoV stainless steel gear shafts used in aviation.

[0005] The technical problem to be solved by this invention is achieved by the following technical solution:

[0006] A method for high-speed laser cladding additive repair of 1Cr11Ni2W2MoV stainless steel gear shafts for aerospace applications includes the following steps:

[0007] (1) Measure the dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft, remove the oxide film on the outer surface of the 1Cr11Ni2W2MoV stainless steel gear shaft, grind and clean the damaged area, measure the dimensions of the damaged area, obtain the width and depth of the damaged area perpendicular to the end face of the pipe fitting, and determine the maximum damage depth.

[0008] (2) Select a set of parameters within the range of laser power 800-1000W, powder feeding speed 1-2r / min, and rotation speed 120-240r / min as high-speed laser cladding process parameters. Substitute the high-speed laser cladding process parameters into the relationship between the single-pass cladding layer height and the relationship between the high-speed laser cladding process parameters and energy density to calculate the single-pass cladding layer height and energy density. Determine whether the single-pass cladding layer height is greater than 1.1 times the maximum damage depth and the energy density value is within the range of 3.3-7. If the conditions are met, select the parameter as the subsequent cladding repair parameter.

[0009] (3) Determine the width of the single-pass cladding layer based on the relationship between the high-speed laser cladding process parameters and the width of the single-pass cladding layer;

[0010] (4) Determine the laser scanning speed based on the determined width of the single cladding layer and the relationship between the width of the single cladding layer and the laser scanning speed;

[0011] (5) Determine the laser working time based on the determined laser scanning speed and the relationship between the laser scanning speed and the laser working time;

[0012] (6) Set the determined high-speed laser cladding process parameters, laser scanning speed and laser working time in the high-speed laser cladding equipment, and then perform high-speed laser cladding repair on the 1Cr11Ni2W2MoV stainless steel gear shaft.

[0013] (7) Stress-relieving annealing treatment was carried out on the 1Cr11Ni2W2MoV stainless steel gear shaft after high-speed laser cladding repair.

[0014] (8) Based on the original dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft, the excess cladding layer on the surface of the 1Cr11Ni2W2MoV stainless steel gear shaft is removed by machining and restored to the original dimensions.

[0015] As a further improvement of the present invention, the dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft in step (1) include a diameter of 8mm-15mm.

[0016] As a further improvement of the present invention, in step (1), sandpaper is used to polish the damaged area, requiring the bottom of the damaged area to be flat and the sidewalls to be smoothly connected to the bottom. Acetone is used to clean the damaged area, and the measured damage depth is 1-300μm.

[0017] As a further improvement of the present invention, the relationship between the high-speed laser cladding process parameters and the height of the single-pass cladding layer in step (2) is as follows:

[0018] Single-pass cladding layer height = 0.04678 * laser power + 153.05233 * powder feeding speed - 1.03155 * rotation speed + 135.24322.

[0019] As a further improvement of the present invention, the relationship between the high-speed laser cladding process parameters and the energy density in step (2) is as follows:

[0020] Energy density = laser power / rotation speed.

[0021] As a further improvement of the present invention, the relationship between the high-speed laser cladding process parameters and the width of the single-pass cladding layer in step (3) is as follows:

[0022] Single-pass cladding layer width = 0.53489 * laser power - 95.708 * powder feeding speed - 1.73632 * rotation speed + 1021.71072.

[0023] As a further improvement of the present invention, the relationship between the width of the single-pass cladding layer and the laser scanning speed in step (4) is as follows:

[0024] Laser scanning speed = cladding width of a single cladding pass * rotation speed / 120.

[0025] As a further improvement of the present invention, the relationship between the laser scanning speed and the laser working time in step (5) is as follows:

[0026] Laser working time = width of damaged area + 2mm / laser scanning speed.

[0027] As a further improvement of the present invention, the high-speed laser cladding process parameters in step (6) also include: the cladding powder is the same 1Cr11Ni2W2MoV metal powder as the base material, the powder particle size is 20-53um, the powder feeding gas flow rate is 4L / min, the central protective gas flow rate is 8L / min, the powder spot diameter at the powder convergence focal point of the cladding head is 1mm-1.5mm, the laser spot diameter is 1mm-1.2mm, and during laser cladding repair, the powder focus converges on the surface of the part to be repaired.

[0028] As a further improvement of the present invention, the stress relief annealing process in step (7) is as follows: the 1Cr11Ni2W2MoV stainless steel gear shaft after high-speed laser cladding repair is placed in an atmosphere furnace at a temperature of 200-240℃ and kept at that temperature for 2 hours. The protective atmosphere in the atmosphere furnace is argon. After the heat preservation is completed, the gear shaft is cooled with the furnace.

[0029] The beneficial effects of this invention are:

[0030] This invention provides a method for high-speed laser cladding additive repair of 1Cr11Ni2W2MoV stainless steel gear shafts used in aviation. It can achieve high-quality repair of damaged 1Cr11Ni2W2MoV stainless steel gear shafts, facilitate the repair work of testers and operators, and provide theoretical guidance and practical repair cases for the repair of related parts and accessories. Attached Figure Description

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0032] Figure 1 This is a cross-sectional topography of a single cladding layer in the embodiment;

[0033] Figure 2 The image shows the macroscopic morphology of the surface of a 1Cr11Ni2W2MoV stainless steel gear shaft after repair.

[0034] Figure 3 Microstructure of the cladding layer after repair of a 1Cr11Ni2W2MoV stainless steel gear shaft. Detailed Implementation

[0035] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] A large area of ​​wear appeared on the outer surface of the 1Cr11Ni2W2MoV gear shaft in the cooling pump of a certain type of aircraft cooling system. The diameter of the 1Cr11Ni2W2MoV gear shaft ranged from 8mm to 15mm, and the damage depth of the damaged area ranged from 1 to 300μm.

[0037] A method for repairing aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts using high-speed laser cladding additive manufacturing was employed, including the following steps:

[0038] (1) Measure the dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft, remove the oxide film on the outer surface of the 1Cr11Ni2W2MoV stainless steel gear shaft, polish with sandpaper, clean the damaged area with acetone, measure the dimensions of the damaged area, obtain the width and depth of the damaged area perpendicular to the end face of the pipe fitting, and determine the maximum damage depth.

[0039] In this embodiment, the diameter of the 1Cr11Ni2W2MoV gear shaft is 10mm, the damage depth of the damaged area is 138μm, and the width of the damaged area is 40mm.

[0040] (2) The laser power of 900W, the powder feeding speed of 1.5r / min, and the gear shaft rotation speed of 240r / min were selected as the high-speed laser cladding process parameters. Substituting these parameters into the relationship between the high-speed laser cladding process parameters and the height of the single-pass cladding layer, the relationship between the high-speed laser cladding process parameters and the height of the single-pass cladding layer is as follows:

[0041] Single-pass cladding layer height = 0.04678 * laser power + 153.05233 * powder feeding speed - 1.03155 * rotation speed + 135.24322.

[0042] The relationship between high-speed laser cladding process parameters and energy density is as follows:

[0043] Energy density = laser power / rotation speed.

[0044] The calculated height of the single-pass cladding layer is 159 μm. Since 159 > 1.1 * 138 and the energy density is 3.75, falling within the range of 3.3-7, this parameter is selected as the subsequent cladding repair parameter. The cross-sectional morphology of the single-pass cladding layer is shown below. Figure 1 As shown.

[0045] (3) Based on the relationship between the high-speed laser cladding process parameters and the width of a single cladding layer: width of a single cladding layer = 0.53489 * laser power - 95.708 * powder feeding speed - 1.73632 * rotation speed + 1021.71072, the width of a single cladding layer is determined to be 943 μm.

[0046] (4) Based on the determined width of the single cladding layer and the relationship between the width of the single cladding layer and the laser scanning speed: laser scanning speed = width of a single cladding pass * rotation speed / 120, the laser scanning speed is determined to be 1.885 mm / s.

[0047] (5) Based on the determined laser scanning speed and the relationship between laser scanning speed and laser working time: laser working time = damage area width + 2mm / laser scanning speed, the laser working time is determined to be 22.3s.

[0048] (6) Set the determined high-speed laser cladding process parameters, laser scanning speed and laser working time in the high-speed laser cladding equipment, and perform high-speed laser cladding repair on the 1Cr11Ni2W2MoV stainless steel gear shaft.

[0049] The high-speed laser cladding process parameters also include: the cladding powder is the same 1Cr11Ni2W2MoV metal powder as the base material, with a particle size between 20-53µm; the powder feed gas flow rate is 4L / min; the central protective gas flow rate is 8L / min; the powder spot diameter at the powder convergence point of the cladding head is 1.5mm; and the laser spot diameter is 1mm. During laser cladding repair, the powder focus converges on the surface of the part to be repaired, and high-speed laser cladding repair is performed on the 1Cr11Ni2W2MoV stainless steel gear shaft.

[0050] After repair, the macroscopic morphology of the 1Cr11Ni2W2MoV stainless steel gear shaft is as follows: Figure 2 As shown, the microstructure morphology of the cladding layer is as follows: Figure 3 As shown, the hardness of the 1Cr11Ni2W2MoV stainless steel gear shaft base is 443.0 HV, and the hardness of the cladding layer is 486.9 HV. After repair, the hardness is higher than that of the base, which meets the usage requirements.

[0051] (7) The 1Cr11Ni2W2MoV stainless steel gear shaft after high-speed laser cladding repair is placed in an atmosphere furnace at 230℃ for 2 hours. The protective atmosphere in the atmosphere furnace is argon. After the heat preservation is completed, the gear shaft is cooled with the furnace.

[0052] (8) Based on the original dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft, the excess cladding layer on the surface of the 1Cr11Ni2W2MoV stainless steel gear shaft is removed by machining and restored to the original dimensions.

[0053] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for high-speed laser cladding additive repair of 1Cr11Ni2W2MoV stainless steel gear shafts for aerospace applications, characterized in that: Includes the following steps: (1) Measure the dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft, remove the oxide film on the outer surface of the 1Cr11Ni2W2MoV stainless steel gear shaft, grind and clean the damaged area, measure the dimensions of the damaged area, obtain the width and depth of the damaged area perpendicular to the end face of the pipe fitting, and determine the maximum damage depth. (2) Select a set of parameters within the range of laser power 800-1000W, powder feeding speed 1-2r / min, and rotation speed 120-240r / min as high-speed laser cladding process parameters. Substitute the high-speed laser cladding process parameters into the relationship between the single-pass cladding layer height and the relationship between the high-speed laser cladding process parameters and energy density to calculate the single-pass cladding layer height and energy density. Determine whether the single-pass cladding layer height is greater than 1.1 times the maximum damage depth and the energy density value is within the range of 3.3-7. If the conditions are met, select the parameter as the subsequent cladding repair parameter. (3) Determine the width of a single cladding layer based on the relationship between the high-speed laser cladding process parameters and the width of a single cladding layer; (4) Determine the laser scanning speed based on the determined width of the single cladding layer and the relationship between the width of the single cladding layer and the laser scanning speed; (5) Determine the laser working time based on the determined laser scanning speed and the relationship between the laser scanning speed and the laser working time; (6) Set the determined high-speed laser cladding process parameters, laser scanning speed and laser working time in the high-speed laser cladding equipment, and then perform high-speed laser cladding repair on the 1Cr11Ni2W2MoV stainless steel gear shaft. The powder particle size used for cladding is 20-53um. (7) The 1Cr11Ni2W2MoV stainless steel gear shaft after high-speed laser cladding repair is subjected to stress-relieving annealing treatment at a temperature of 200-240℃ and held for 2 hours. (8) Based on the original dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft, remove the excess cladding layer on the surface of the 1Cr11Ni2W2MoV stainless steel gear shaft by machining and restore it to its original dimensions. The relationship between the high-speed laser cladding process parameters and the single-pass cladding layer height in step (2) is: The relationship between the high-speed laser cladding process parameters and the energy density in step (2) is: Energy density = laser power / rotation speed; the relationship between the high-speed laser cladding process parameters and the width of a single cladding layer in step (3) is as follows: The width of a single cladding layer = 0.53489 * laser power - 95.708 * powder feeding speed - 1.73632 * rotation speed + 1021.71072; the relationship between the width of a single cladding layer and the laser scanning speed in step (4) is as follows: Laser scanning speed = cladding width of a single cladding pass * rotation speed / 120; the relationship between laser scanning speed and laser working time in step (5) is: Laser working time = width of damaged area + 2mm / laser scanning speed; The hardness of the cladding layer is 486.9 HV.

2. The method for high-speed laser cladding additive repair of aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts according to claim 1, characterized in that: In step (1), the dimensions of the 1Cr11Ni2W2MoV stainless steel gear shaft include diameters of 8mm-15mm.

3. The method for high-speed laser cladding additive repair of aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts according to claim 1, characterized in that: In step (1), the damaged area is polished with sandpaper. The bottom of the damaged area is required to be flat and the sidewalls are smoothly connected to the bottom. The damaged area is cleaned with acetone. The measured damage depth is 1-300μm.

4. The method for high-speed laser cladding additive repair of aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts according to claim 1, characterized in that: In step (6), the high-speed laser cladding process parameters also include: the cladding powder is the same 1Cr11Ni2W2MoV metal powder as the base material, the powder feeding gas flow rate is 4L / min, the central protective gas flow rate is 8L / min, the powder spot diameter at the powder convergence focal point of the cladding head is 1mm-1.5mm, the laser spot diameter is 1mm-1.2mm, and during laser cladding repair, the powder focus converges on the surface of the part to be repaired.

5. The method for high-speed laser cladding additive repair of aerospace-grade 1Cr11Ni2W2MoV stainless steel gear shafts according to claim 1, characterized in that: The stress-relief annealing process in step (7) is as follows: the 1Cr11Ni2W2MoV stainless steel gear shaft repaired by high-speed laser cladding is placed in an atmosphere furnace, the protective atmosphere in the atmosphere furnace is argon, and after the heat preservation is completed, it is cooled with the furnace.

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