Titanium alloy rotor blade tip size fast repair method

Abstract

The application discloses a kind of titanium alloy rotor blade tip size fast repair method, comprising the following steps:1) polishing tip: remove extra tip grinding;2) tip cleaning;Contaminants on the blade are removed with cleaning agent;3) blade protection: the part of blade body that does not need to be repaired is shielded and protected using protective material;4) tip roughening: sand blasting roughening is used to the tip, so that the roughness of blade tip reaches 5 μm-7 μm;5) tip spraying: WC / CoCrNi powder is used to repair the size of blade tip by plasma spraying;The distance of plasma spraying powder is: 140mm-145mm;Spraying angle is 45°-60°;WC / CoCrNi powder particle size is (10-20) μm, and WC / CoCrNi powder fluidity is greater than or equal to 45g / 50S;The method has the characteristics of simple repair process, strong self-adaptability, high efficiency, low cost and suitability for batch repair.Meanwhile, the wear resistance of the repaired tip is strong, the matching with the matrix is good, and the service life is long.

Description

Technical Field

[0001] This invention relates to the field of aero-engine maintenance technology, and in particular to a method for rapid repair of the tip size of titanium alloy rotor blades. Background Technology

[0002] To reduce the weight of aero engines, the low-pressure compressor rotor blades are generally made of titanium alloy. These blades are ultra-thin, irregularly shaped curved structures that operate under complex conditions of high temperature and high pressure. During service, the blade tips of the titanium alloy compressor rotor blades may become smaller in size due to friction and wear with the stator assembly of the compressor casing. This leads to an increase in the clearance between the compressor rotor and stator, thus affecting the engine's aerodynamic efficiency. During subsequent overhauls, to ensure the aerodynamic efficiency of the compressor assembly, the compressor blades need to be extended and repaired or replaced with new ones.

[0003] To achieve dimensional repair of titanium alloy rotor blade tips, it is necessary to consider the unique characteristics of its material and structure. Regarding materials, for the repair of worn titanium alloy parts, patent CN109338271A proposes using plasma spraying of nickel-aluminum powder to repair circular stops. However, this method involves spraying a coating onto the surface of a circular part of a certain width, where molten powder easily accumulates and adheres. For blade tips with thin-walled, irregularly curved surfaces, directly applying existing surface repair methods for titanium alloy parts cannot achieve effective material accumulation, nor can it guarantee the formation of a thin-walled, irregularly curved surface structure after repair. Furthermore, it cannot guarantee the strength requirements of the titanium alloy blade tip during use, or the fit requirements with the stator casing assembly.

[0004] Structurally, for blade tip parts with thin-walled, irregularly curved surfaces, laser cladding or micro-beam plasma arc welding are generally used for extension and repair. These two methods require significant equipment investment, involve large amounts of weld overlay to meet the blade profile requirements after repair, and result in a large workload and high difficulty in subsequent reshaping. Furthermore, to ensure the quality of the extended blade, a series of complex processes such as stress-relieving heat treatment and acid pickling are required, leading to low extension efficiency and making it unsuitable for batch blade repair. To address this, patent CN202310292379.7 proposes using supersonic flame spraying to extend and repair the tips of high-temperature alloy high-pressure compressor rotor blades. However, this method is designed for high-temperature alloy compressor rotor blades. During supersonic flame spraying, the high-flow-rate, high-temperature combustion gas repeatedly erodes the thin-walled titanium alloy blades, easily causing oxidation and bluing on the titanium alloy surface. Therefore, this repair method is unsuitable for repairing titanium alloy blades. Meanwhile, the impact force generated by the gas during supersonic flame spraying is significant, requiring specialized tooling to fix the blades and protect the non-sprayed areas. Adjustments to the gap between the blade shielding components and the blades are also necessary during the spraying process, making the tooling design complex and costly. Finally, to ensure the molten powder can be deposited on the blade tip, this method also includes a 2-3 mm area on the blade body as the coating deposition zone. This easily creates a step between the coating deposition area and the non-deposition area on the blade body, affecting the blade's aerodynamic performance. In other words, this method is a repair method that primarily sacrifices blade aerodynamic performance.

[0005] In summary, existing repair methods either only consider the material properties of the titanium alloy blade tip and cannot effectively take into account the structural requirements of the repaired parts; or they only consider the structural properties of the titanium alloy blade tip and cannot effectively take into account the oxidation and bluing caused by the erosion of the titanium alloy material during repair. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for rapid repair of the tip size of titanium alloy rotor blades.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for rapid repair of the tip size of titanium alloy rotor blades includes the following steps:

[0009] 1) Grinding the blade tips: Grinding away excess blade tips;

[0010] 2) Leaf tip cleaning; use a cleaning agent to remove contaminants from the leaves;

[0011] 3) Blade protection: Protective materials are used to shield and protect the blade parts that do not need repair; due to the low scouring force of plasma spraying, this invention does not require the use of special tooling to fix the blades or protect the non-sprayed areas of the blades, and steps are not easily formed between the coating deposition area and the non-deposition area of ​​the blade.

[0012] 4) Blade tip roughening: Sandblasting is used to roughen the blade tip, so that the roughness of the blade tip reaches 5μm to 7μm; the blade roughness is within a suitable range, which is conducive to the deposition and accumulation of more spray powder on the surface.

[0013] 5) Blade tip spraying: The blade tip is repaired by plasma spraying WC / CoCrNi powder; the distance of plasma spraying is 140mm~145mm; the spraying angle is 45°~60°; the particle size of WC / CoCrNi powder is (10~20)μm; and the flowability of WC / CoCrNi powder is ≥45g / 50S.

[0014] Furthermore, in step 2), an alkaline cleaning agent is used to clean the blades in an ultrasonic environment; the cleaning temperature is 50℃~70℃, and the cleaning time is 15min~30min; the combination of ultrasonic cleaning and alkaline cleaning at a suitable cleaning temperature is beneficial for removing oily contaminants from the blade surface, which is beneficial for subsequent powder coating to be deposited at the tip of the blade.

[0015] Furthermore, in step 3), protective tape is used to wrap around the blade body, leaving only the blade tip exposed; the protective tape used in this invention is a high-temperature resistant tape.

[0016] Furthermore, in step 5), after spraying, the coating thickness is 0.1mm to 0.5mm; the coating adhesion strength is ≥60MPa; and the coating microhardness is HV. 0.3 The coating thickness is 750-850; the air-cooled thermal shock resistance at 550℃ is ≥600 cycles; once the coating thickness, bonding strength, microhardness and air-cooled thermal shock resistance meet the requirements, it will be beneficial to achieve good matching performance with titanium alloy blades and ensure that the repaired blade tip can meet the requirements under operating conditions.

[0017] Furthermore, in step 5), the parameters used in the plasma spraying process are: argon flow rate of 70-75 NLPM; hydrogen flow rate of 4-5 NLPM; current of 580A-600A; and powder feeding rate of 30 g / min-35 g / min. This invention increases the argon flow rate from the conventional 20-40 NLPM to 70-75 NLPM. By increasing the argon flow rate, the flight speed of the molten powder particles is accelerated, which is beneficial for the stacking and growth of WC / CoCrNi powder at the tip of the thin-walled irregular curved blade. At the same time, the prepared coating has less oxidation, lower porosity, and higher bonding strength.

[0018] Furthermore, in step 5), the WC / CoCrNi powder is prepared by mixing WC powder and CoCrNi powder, adding deionized water and binder, and ball milling. After ball milling, the mixture is atomized and granulated to obtain spherical powder, which is then vacuum sintered, crushed, and sieved. The WC / CoCrNi powder of this invention is prepared using a special process. The CoCrNi powder is mainly used to increase the thermal compatibility with the high-temperature alloy substrate, while WC plays a role in adjusting the coating hardness. Under the combined effect of the two, the hardness requirements of the coating during high-temperature use are guaranteed, and peeling will not occur due to inconsistency in thermal compatibility with the substrate. At the same time, by controlling the selection of powder materials and the preparation method, the particle size of the powder can be adjusted, laying the foundation for subsequent control of coating roughness. If the roughness of the repaired coating is too large or too small, the aerodynamic performance of the blade will be affected. In addition, after vacuum sintering, the hardness of the spherical powder is further improved at high temperatures. Meanwhile, the binder may form micropores on the material surface after burning off at high temperatures, increasing the specific surface area of ​​the material, so that the repair powder can be deposited better.

[0019] Furthermore, in step 5), when preparing WC / CoCrNi powder, the weight fraction of WC powder is 50-60 parts, and the particle size is 15μm-45μm; the weight fraction of CoCrNi powder is 40-50 parts, and the particle size is 15μm-45μm. The weight fraction and particle size selection of WC powder and CoCrNi powder when preparing WC / CoCrNi powder will affect the particle size of the prepared WC / CoCrNi powder, its thermal matching performance with titanium alloy materials, bonding strength, and overall performance such as hardness and roughness.

[0020] Furthermore, according to parts by weight, the CoCrNi powder comprises 18 to 21 parts of chromium, 13 to 18 parts of nickel, and the remainder is cobalt;

[0021] A further technical solution is that the adhesive includes one or more of polyvinyl alcohol, polyisobutylene, and polyvinyl acetate. In this invention, a polymeric organic adhesive is selected as the adhesive. The raw material powder is combined under the action of the organic polymer, and under vacuum sintering, the raw material powder forms sprayable particles with controllable flowability and particle size that meet the requirements.

[0022] The present invention has the following advantages:

[0023] 1. No further treatment required after spraying: Compared with fusion welding methods such as laser and argon arc welding, this method can determine the amount of repair based on the actual wear of the blade tip. After spraying, there is no need for time-consuming processes such as grinding and stress relief. It can be used directly after spraying. It has the characteristics of low heat input, simple process, short repair cycle, fast repair speed, and can realize rapid repair of the blade tip of titanium alloy compressor rotor.

[0024] 2. Achieving a balance between structural and material performance: This invention controls the coating's performance and roughness by rationally designing the powder composition, particle size, and flowability. Simultaneously, a suitable spraying angle ensures that the sprayed blade tip coating material effectively adheres to the tip of the thin-walled, irregularly curved blade, exhibiting excellent compatibility with the titanium alloy. This guarantees that the repaired blade tip meets the requirements of operating conditions. Preferably, during coating preparation, increasing the argon flow rate accelerates the flight speed of the molten powder particles, resulting in a coating with less oxidation, lower porosity, and higher bonding strength, ensuring good adhesion between the coating and the substrate. Furthermore, the coupled effect of powder and spraying parameters achieves moderate coating hardness and roughness, ensuring a good match between the extended blade tip and the stator sealing coating, while also providing excellent aerodynamic performance. The plasma spraying method, with its lower gas flow rate, mitigates the erosion of the thin-walled titanium alloy blade, making the repaired rotor blade less prone to surface oxidation and bluing.

[0025] 3. Easy blade protection: Due to the low impact force of the plasma flame, blade protection is relatively easy. It can be directly protected with tape. Simply wrap the tape around the blade that does not need repair. Therefore, the blades can be arranged in a row or a circle for spraying according to the production situation, which is highly flexible. For production enterprises, it can repair in large batches and improve repair efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the blade spraying position in this invention.

[0027] Figure 2 This is a schematic diagram of the blade structure in this invention.

[0028] In the picture: 1. Leaf. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0034] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Example 1: A method for rapid repair of the tip size of titanium alloy rotor blades, specifically including the following steps:

[0036] 1) Grinding the blade tips: Grinding away excess blade tips;

[0037] 2) Leaf tip cleaning; use a cleaning agent to remove contaminants from the leaves;

[0038] 3) Leaf protection: Use protective materials to cover and protect the parts of the leaf that do not require repair;

[0039] 4) Leaf tip roughening: The leaf tip is roughened by sandblasting to achieve a roughness of 5μm to 7μm.

[0040] 5) Blade tip spraying: The blade tip is repaired by plasma spraying WC / CoCrNi powder; the distance of plasma spraying is 140mm~145mm; the spraying angle is 45°~60°; the particle size of WC / CoCrNi powder is (10~20)μm; the flowability of WC / CoCrNi powder is ≥45g / 50S;

[0041] In step 2), an alkaline cleaning agent is used to clean the blades in an ultrasonic environment; the cleaning temperature is 50℃~70℃, and the cleaning time is 15min~30min.

[0042] In step 3), protective tape is used to wrap the blade body, leaving only the blade tip exposed;

[0043] In step 5), after spraying, the coating thickness is 0.1mm to 0.5mm; the coating bonding strength is ≥60MPa; and the coating microhardness is HV. 0.3 The coating has a thermal shock resistance of 750-850°C at 550°C, with a thermal shock resistance of ≥600 cycles.

[0044] In step 5), the parameters used in the plasma spraying process are: argon flow rate of 70-75 NLPM; hydrogen flow rate of 4-5 NLPM; current of 580A-600A; and powder feeding rate of 30 g / min-35 g / min.

[0045] In step 5), the WC / CoCrNi powder is obtained by mixing WC powder and CoCrNi powder, adding deionized water and binder, and then ball milling; after ball milling, the mixture is atomized and granulated to obtain spherical powder, which is then vacuum sintered, crushed, and sieved.

[0046] In step 5), when preparing WC / CoCrNi powder, the weight fraction of WC powder is 50-60 parts and the particle size is 15μm-45μm; the weight fraction of CoCrNi powder is 40-50 parts and the particle size is 15μm-45μm.

[0047] According to the weight parts, the CoCrNi powder comprises 18 to 21 parts of chromium, 13 to 18 parts of nickel, and the remainder is cobalt;

[0048] The adhesive includes one or more of polyvinyl alcohol, polyisobutylene, and polyvinyl acetate.

[0049] Example 2: The rotor blades of the low-pressure first-stage compressor of a certain type of engine, made of TC4 titanium alloy, consist of 32 pieces. After service, the blade tips showed wear ranging from 0.1 to 0.2 mm. A rapid repair method for the blade tip size of titanium alloy rotor blades was used for repair, specifically including the following steps:

[0050] 1) Grinding the blade tip: Remove excess blade tip material by grinding; In this embodiment, the blade tip is ground using an automatic grinding machine. The titanium alloy compressor rotor blade is installed in the material tray of the automatic grinding machine. The robot automatically grabs the blade and moves the blade tip to a rotating abrasive belt with a linear velocity of 2m / s from the reference position at a feed rate of 0.2mm, a feed speed of 0.03mm / s, and a lateral movement speed of 0.08mm / s, grinding the blade to a uniform height.

[0051] 2) Leaf tip cleaning; use a cleaning agent to remove contaminants from the leaves;

[0052] 3) Leaf protection: Use protective materials to cover and protect the parts of the leaf that do not require repair;

[0053] 4) Leaf tip roughening: The leaf tip is roughened by sandblasting, so that the roughness of the leaf tip reaches 5.8μm;

[0054] 5) Blade tip spraying: Plasma spraying of WC / CoCrNi powder is used to repair the size of the blade tip; the distance of plasma spraying is 140mm; the spraying angle is 45°; the particle size of WC / CoCrNi powder is (10~20)μm; and the flowability of WC / CoCrNi powder is 48g / 50S.

[0055] In step 2), an alkaline cleaning agent is used to clean the blades in an ultrasonic environment; the cleaning temperature is 55°C and the cleaning time is 15 minutes.

[0056] In step 3), protective tape is used to wrap the blade body, leaving only the blade tip exposed;

[0057] In step 5), after spraying, the coating thickness is 0.20 mm to 0.25 mm; the coating adhesion strength is 62 MPa; and the coating microhardness is HV. 0.3 The coating has a thermal shock resistance of 780 at 550°C and undergoes 642 cycles of air cooling and thermal shock at 550°C.

[0058] In step 5), the parameters used in the plasma spraying process are: argon flow rate of 70 NLPM; hydrogen flow rate of 4.0 NLPM; current of 580 A; and powder feeding rate of 30 g / min.

[0059] In step 5), the WC / CoCrNi powder is obtained by mixing WC powder and CoCrNi powder, adding deionized water and binder, and then ball milling; after ball milling, the mixture is atomized and granulated to obtain spherical powder, which is then vacuum sintered, crushed, and sieved.

[0060] In step 5), when preparing WC / CoCrNi powder, the weight fraction of WC powder is 52 parts and the particle size is 15μm to 45μm; the weight fraction of CoCrNi powder is 48 parts and the particle size is 15μm to 45μm.

[0061] The CoCrNi powder comprises 20 parts chromium, 15 parts nickel, and the remainder cobalt by weight.

[0062] The adhesive is polyvinyl alcohol.

[0063] Example 3: The rotor blades of the low-pressure first-stage compressor of a certain type of engine, made of TC4 titanium alloy, consist of 30 pieces. After service, the blade tips showed wear ranging from 0.2 mm to 0.3 mm. A rapid repair method for the blade tip size of titanium alloy rotor blades was used for repair, specifically including the following steps:

[0064] 1) Grinding the blade tips: Grinding away excess blade tips;

[0065] 2) Leaf tip cleaning; use a cleaning agent to remove contaminants from the leaves;

[0066] 3) Leaf protection: Use protective materials to cover and protect the parts of the leaf that do not require repair;

[0067] 4) Leaf tip roughening: The leaf tip is roughened by sandblasting, so that the roughness of the leaf tip reaches 6.3μm;

[0068] 5) Blade tip spraying: The blade tip is repaired by plasma spraying WC / CoCrNi powder; the distance of plasma spraying is 142mm; the spraying angle is 50°; the particle size of WC / CoCrNi powder is (10~20)μm; and the flowability of WC / CoCrNi powder is 52g / 50S.

[0069] In step 2), an alkaline cleaning agent is used to clean the blades using ultrasound; the cleaning temperature is 65℃ and the cleaning time is 25 minutes.

[0070] In step 3), protective tape is used to wrap the blade body, leaving only the blade tip exposed;

[0071] In step 5), after spraying, the coating thickness is 0.3mm to 0.35mm; the coating adhesion strength is 68MPa; and the coating microhardness is HV. 0.3 The coating is 802; its air-cooled thermal shock resistance at 550℃ is 645 cycles.

[0072] In step 5), the parameters used in the plasma spraying process are: argon flow rate of 72 NLPM; hydrogen flow rate of 4.5 NLPM; current of 590A; and powder feeding rate of 32 g / min.

[0073] In step 5), the WC / CoCrNi powder is obtained by mixing WC powder and CoCrNi powder, adding deionized water and binder, and then ball milling; after ball milling, the mixture is atomized and granulated to obtain spherical powder, which is then vacuum sintered, crushed, and sieved.

[0074] In step 5), when preparing WC / CoCrNi powder, the weight fraction of WC powder is 55 parts and the particle size is 15μm to 45μm; the weight fraction of CoCrNi powder is 45 parts and the particle size is 15μm to 45μm.

[0075] The CoCrNi powder comprises 18 parts chromium, 13 parts nickel, and the remainder cobalt by weight.

[0076] The adhesive is polyisobutylene.

[0077] Example 4: The rotor blades of the low-pressure first-stage compressor of a certain type of engine, made of TC4 titanium alloy, consist of 35 pieces. After service, the blade tips showed wear ranging from 0.3 to 0.5 mm. A rapid repair method for the blade tip size of titanium alloy rotor blades was used for repair, specifically including the following steps:

[0078] 1) Grinding the blade tips: Grinding away excess blade tips;

[0079] 2) Leaf tip cleaning; use a cleaning agent to remove contaminants from the leaves;

[0080] 3) Leaf protection: Use protective materials to cover and protect the parts of the leaf that do not require repair;

[0081] 4) Leaf tip roughening: The leaf tip is roughened by sandblasting to achieve a roughness of 7.0 μm.

[0082] 5) Blade tip spraying: Plasma spraying of WC / CoCrNi powder is used to repair the size of the blade tip; the distance of plasma spraying is 145mm; the spraying angle is 60°; the particle size of WC / CoCrNi powder is (10~20)μm; and the flowability of WC / CoCrNi powder is 55g / 50S.

[0083] In step 2), an alkaline cleaning agent is used to clean the blades in an ultrasonic environment; the cleaning temperature is 70°C and the cleaning time is 30 minutes.

[0084] In step 3), protective tape is used to wrap the blade body, leaving only the blade tip exposed;

[0085] In step 5), after spraying, the coating thickness is 0.50 mm to 0.55 mm; the coating adhesion strength is 74 MPa; and the coating microhardness is HV. 0.3 The value is 820; the coating's air-cooled thermal shock resistance at 550℃ is 650 cycles.

[0086] In step 5), the parameters used in the plasma spraying process are: argon flow rate of 75 NLPM; hydrogen flow rate of 5 NLPM; current of 600A; and powder feeding rate of 35g / min.

[0087] In step 5), the WC / CoCrNi powder is obtained by mixing WC powder and CoCrNi powder, adding deionized water and binder, and then ball milling; after ball milling, the mixture is atomized and granulated to obtain spherical powder, which is then vacuum sintered, crushed, and sieved.

[0088] In step 5), when preparing WC / CoCrNi powder, the weight fraction of WC powder is 58 parts and the particle size is 15μm to 45μm; the weight fraction of CoCrNi powder is 42 parts and the particle size is 15μm to 45μm.

[0089] The CoCrNi powder comprises 21 parts chromium, 18 parts nickel, and the remainder cobalt by weight.

[0090] The adhesive is polyvinyl acetate.

[0091] Comparative Example 1: The rotor blades of the low-pressure first-stage compressor of a certain type of engine were repaired using the method of Example 2. The only difference was that the distance during plasma powder spraying was 100mm and the spraying angle was 75°. After spraying, the coating thickness was 0.20mm~0.25mm; the coating adhesion strength was 48MPa; and the coating microhardness was HV. 0.3 The value is 215; the coating's thermal shock resistance at 550℃ is 35 cycles.

[0092] Comparative Example 2: The method of Example 2 was used to repair the rotor blades of the low-pressure first-stage compressor of a certain type of engine. The only difference was that the plasma spraying powder was nickel-based powder, mainly composed of 75.5% nickel, 18.5% chromium, and 6% aluminum, with a particle size of -125 ± 45 μm. After spraying, the coating thickness was 0.20 mm to 0.25 mm; the coating adhesion strength was 64 MPa; and the coating microhardness was HV. 0.3 The value is 454; the coating's thermal shock resistance at 550℃ is 647 cycles.

[0093] Comparative Example 3: The rotor blades of the low-pressure first-stage compressor of a certain type of engine were repaired using the method of Example 2, with the only difference being that during plasma spraying, the argon flow rate was 20-30 NLPM and the hydrogen flow rate was 3-5 NLPM. After spraying, the coating thickness was 0.20 mm-0.25 mm; the coating adhesion strength was 42 MPa; and the coating microhardness HV was... 0.3 The value is 620; the coating's air-cooled thermal shock resistance at 550℃ is 615 cycles.

[0094] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of rapid repair of a titanium alloy rotor blade tip size, characterized by, Includes the following steps: 1) Grinding the blade tips: Grinding away excess blade tips; 2) Leaf tip cleaning; use a cleaning agent to remove contaminants from the leaves; 3) Leaf protection: Use protective materials to cover and protect the parts of the leaf that do not require repair; 4) Leaf tip roughening: The leaf tip is roughened by sandblasting to achieve a roughness of 5μm to 7μm. 5) Blade tip spraying: The blade tip is repaired by plasma spraying with WC / CoCrNi powder; the distance of plasma spraying is 140mm~145mm; the spraying angle is 45°~60°; the particle size of WC / CoCrNi powder is (10~20)μm; the flowability of WC / CoCrNi powder is ≥45g / 50S; in step 5), after spraying, the coating thickness is 0.1mm~0.5mm; the bonding strength of the coating is ≥60MPa; the microhardness of the coating is HV. 0.3 The coating has a thermal shock resistance of ≥600 cycles under air cooling at 550℃. In step 5), the parameters used in the plasma spraying process are: argon flow rate of 70-75 NLPM; hydrogen flow rate of 4-5 NLPM; current of 580A-600A; and powder feeding rate of 30 g / min-35 g / min. In step 5), the WC / CoCrNi powder is prepared by mixing WC powder and CoCrNi powder, adding deionized water and binder, and ball milling. After ball milling, the mixture is atomized and granulated to obtain spherical powder. The spherical powder is then vacuum sintered, crushed, and sieved. In step 5), when preparing the WC / CoCrNi powder, the weight fraction of WC powder is 50-60 parts, and the particle size is 15μm-45μm. The weight fraction of CoCrNi powder is 40-50 parts, and the particle size is 15μm-45μm.

2. The method of rapid repair of a titanium alloy rotor blade tip size according to claim 1, wherein: In step 2), an alkaline cleaning agent is used to clean the blades in an ultrasonic environment; the cleaning temperature is 50℃~70℃, and the cleaning time is 15min~30min.

3. The method for rapid repair of the tip size of titanium alloy rotor blades according to claim 1, characterized in that: In step 3), protective tape is used to wrap the blade body, leaving only the blade tip exposed.

4. The method of rapid repair of the titanium alloy rotor blade tip size according to claim 1, characterized in that: According to the weight percentages, the CoCrNi powder comprises 18 to 21 parts of chromium, 13 to 18 parts of nickel, and the remainder is cobalt.

5. The method of rapid repair of the titanium alloy rotor blade tip size according to claim 1, characterized in that: The adhesive includes one or more of polyvinyl alcohol, polyisobutylene, and polyvinyl acetate.

Images