Method for brazing vibration reduction boss of aero-engine fan rotor blade through laser shape correction

Abstract

The invention relates to a method for brazing a vibration reduction boss of a fan rotor blade of an aero-engine through laser correction. The method comprises the following steps that preparation before welding of the fan blade is conducted, and pressure-sensitive adhesive tape is fixed to a blade body and a boss non-welding area; preparing a brazing solder, namely mixing and configuring the Liforce hard alloy powder and the brazing filler metal to form brazing filler metal mixed powder; preparing a Levite adhesive; fully mixing the prepared adhesive and the brazing filler metal mixed powder, and stirring into paste; preparation before laser shape correction brazing is conducted, specifically, the boss is coated with paste brazing filler metal; the coated blade is placed in an environment box, then vacuum pumping is conducted, and argon is filled into the environment box and keeps consistent with the atmospheric pressure; a rectangular flat-topped laser is adopted as shape-righting laser, and the size of a light spot is determined according to a wear-resistant boss of the blade; and inspection after brazing is conducted, specifically, fluorescence and X-ray inspection are adopted, and the welding quality is inspected. The method solves the problem that an induction brazing method easily causes non-uniformity of a wear-resistant layer. The hard alloy on the surface of the wear-resistant layer can be uniformly distributed.

Description

Technical Field

[0001] The invention relates to the field of manufacturing vibration-damping bosses for aircraft engine blades, and in particular to a method for laser orthopedic brazing vibration-damping bosses for aircraft engine fan rotor blades. Background Art

[0002] The fan rotor blades are the key rotating parts of aircraft engines, and they play an important role in transporting air to the inner and outer ducts. When working, aircraft engine blades have to bear large centrifugal loads, aerodynamic loads, thermal loads, and vibration loads. In particular, the probability of blade failure caused by vibration loads is high. In order to solve the vibration problem, fan blades usually use Coulomb friction damping to reduce vibration. A damping vibration reduction structure is added to the blade body of the fan blade. The damping vibration reduction structure can increase the clamping rigidity of the blade ends and increase the natural frequency. During vibration, the working surfaces of the blade damping vibration reduction structure rub against each other to absorb vibration energy, which is also helpful in solving the flutter problem. Therefore, most aircraft engine fan blades at home and abroad use damping vibration reduction structures.

[0003] In order to protect the fan blades and prevent the contact surface of the damping and vibration reduction structure from being worn due to blade vibration, a wear-resistant layer (special carbide coating) is usually sprayed on the contact surface of the damping and vibration reduction structure. The wear-resistant layer is achieved by induction brazing of a paste solder containing wear-resistant particles. When preparing the wear-resistant layer of the blade, multiple processes such as grinding, mixing, solder coating, brazing, and polishing are required. The overall process flow is characterized by high failure rate, short life, high repair cost, and complex repair process. In addition, due to the uneven temperature distribution on the surface of the wear-resistant layer when using induction brazing, there are significant differences in the sedimentation speed of the carbide at different positions, which ultimately causes uneven distribution of carbide on the surface of the wear-resistant layer, resulting in excessive wear size of the wear-resistant layer and causing abnormal vibration of the aircraft engine.

[0004] Therefore, in order to improve the manufacturing and repair efficiency of fan blades, reduce costs, and extend the reliability and service life of the boss wear-resistant layer, it is urgent to develop a new brazing process method. Summary of the invention

[0005] The present invention aims to solve the problem of uneven distribution of hard alloy in the wear-resistant layer caused by induction brazing of the vibration-damping boss of the fan blade of an aircraft engine, and proposes a process method using laser correction brazing. This method can ensure that the distribution of the brazing material is relatively uniform during the brazing process, and can greatly improve the qualified rate of the fan rotor blade vibration-damping boss manufacturing products.

[0006] The present invention is achieved by the following technical solutions:

[0007] A method for laser orthopedic brazing of vibration-damping bosses of fan rotor blades of an aeroengine comprises the following steps:

[0008] Step 1: Preparation before welding the fan blade: fix the pressure-sensitive tape on the non-welding area of ​​the blade body and boss to prevent the laser beam from damaging the blade body;

[0009] Step 2: Preparation of brazing solder: Mix the Lielite cemented carbide powder and the brazing material so that the cemented carbide is evenly dispersed to form a brazing material mixed powder; prepare the Lielite adhesive, the ingredients of which are: acetone, xylene, butyl acetate, and acrylic resin; fully mix the prepared adhesive and the brazing material mixed powder and stir them into a paste;

[0010] Step 3: Preparation before laser brazing: Apply paste solder to the boss, and do not allow it to be applied to the pressure-sensitive tape; place the coated blade in an environmental chamber, and then evacuate it to a pressure less than 5×10 -2 Pa, fill the environmental chamber with argon until it is consistent with the atmospheric pressure;

[0011] Step 4: Laser orthopedic brazing: The orthopedic laser uses a rectangular flat-top laser with a laser power of 2000-3000W. The spot size depends on the blade wear-resistant boss;

[0012] Step 5: Post-brazing inspection: Use fluorescence and X-ray inspection to check the welding quality.

[0013] The Lelite cemented carbide powder and the brazing material in step 2 are mixed in a weight ratio of 30:50;

[0014] The microscopic morphology of the Lelite cemented carbide powder in step 2 is spherical.

[0015] The particle size of the Lelite cemented carbide powder in step 2 is 0.2-0.6 mm.

[0016] In the Lelite adhesive in step 2, the ratio of acetone:xylene:butyl acetate:acrylic resin is 1:2:1:0.2.

[0017] The rectangular flat-top laser spot size in step 4 is 5×2-12×3 mm.

[0018] The laser on time in step 4 is 5-10s.

[0019] Compared with the existing technology, the present invention has the following beneficial effects:

[0020] 1. The cemented carbide powder used in the traditional method is an irregular powder after grinding. The stress distribution of the irregular powder is uneven. When the powder has a sharp angle, stress concentration will occur, thereby reducing the wear resistance of the surface. In the present invention, spherical cemented carbide powder is used, so that the stress distribution during friction and wear is relatively uniform, thereby improving the wear behavior of the surface.

[0021] 2. The traditional method uses the induction brazing method. During the brazing process, due to the uneven distribution of the temperature field, the deposition speed of cemented carbide powders with different morphologies is inconsistent under the action of gravity, resulting in uneven distribution of tungsten carbide particles after brazing; because the wear-resistant properties of the wear-resistant layer are provided by carbide particles, it is also easy to cause uneven wear resistance of the wear-resistant layer. In the present invention, it is first proposed to use a corrective laser brazing method, which can achieve uniform distribution of the energy of the focused spot, so that the brazing material of the wear-resistant layer melts at the same time. Under the premise of uniform distribution of the brazing material, the hard alloy on the surface of the wear-resistant layer can be guaranteed to be evenly distributed, which can greatly improve the wear resistance of the fan blade. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] The following is described by specific examples:

[0024] Example:

[0025] The preparation method of the wear-resistant layer of the second-stage fan blade of a certain type of aircraft engine is as follows:

[0026] Step 1: Preparation before brazing: First, use a file to file the remaining welds and clean the parts to be welded with alcohol or acetone; fix the blade with pressure-sensitive tape to prevent the laser beam from damaging the blade;

[0027] Step 2: Preparation of brazing solder: Mix the Lielite cemented carbide powder and the brazing material in a weight ratio of 30:50 to make the cemented carbide evenly dispersed; and prepare a Lielite adhesive, the ingredients of which are acetone, xylene, butyl acetate, and acrylic resin in a ratio of 1:2:1:0.2; fully mix the prepared adhesive and brazing material mixed powder and stir into a paste;

[0028] Step 3: Preparation before laser brazing: Apply paste solder to the boss, and do not allow it to be applied to the pressure-sensitive tape; place the coated blade in an environmental chamber, and then evacuate it to a pressure less than 5×10 -2 Pa, fill the environmental chamber with argon until it is consistent with the atmospheric pressure;

[0029] Step 4: Laser orthopedic brazing: The orthopedic laser uses a rectangular flat-top laser with a laser power of 2800W, a spot size of 6×2mm, and a laser on time of 5s;

[0030] Step 5: Inspection after brazing: Fluorescence and X-ray inspections were used to check the welding quality, and no cracks or pores were found.

[0031] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for laser orthopedic brazing of vibration-damping bosses of fan rotor blades of aircraft engines, characterized by: The following steps are involved: Step 1: Preparation before welding the fan blade: fix the pressure-sensitive tape on the non-welding area of ​​the blade body and boss to prevent the laser beam from damaging the blade body; Step 2: Preparation of brazing solder: Mix the Lielite cemented carbide powder and the brazing material so that the cemented carbide is evenly dispersed to form a brazing material mixed powder; prepare the Lielite adhesive, the ingredients of which are: acetone, xylene, butyl acetate, and acrylic resin; fully mix the prepared adhesive and the brazing material mixed powder and stir them into a paste; Step 3: Preparation before laser brazing: Apply paste solder to the boss, and do not allow it to be applied to the pressure-sensitive tape; place the coated blade in an environmental chamber, and then evacuate it to a pressure less than 5×10 -2 Pa, fill the environmental chamber with argon until it is consistent with the atmospheric pressure; Step 4: Laser orthopedic brazing: The orthopedic laser uses a rectangular flat-top laser with a laser power of 2000-3000W. The spot size depends on the blade wear-resistant boss; Step 5: Post-brazing inspection: Use fluorescence and X-ray inspection to check the welding quality.

2. The method for laser orthopedic brazing of vibration-damping bosses of fan rotor blades of aircraft engines according to claim 1 is characterized by: The Lelite cemented carbide powder and the brazing material in the step 2 are mixed in a weight ratio of 30:

50.

3. The method for laser orthopedic brazing of vibration-damping bosses of fan rotor blades of aircraft engines according to claim 1 is characterized by: The microscopic morphology of the Lelite cemented carbide powder in step 2 is spherical.

4. The method for laser orthopedic brazing of vibration-damping bosses of fan rotor blades of aircraft engines according to claim 1 is characterized by: The particle size of the Lelite cemented carbide powder in step 2 is 0.2-0.6 mm.

5. The method for laser orthopedic brazing of vibration-damping bosses of aircraft engine fan rotor blades according to claim 1 is characterized by: In the Lelite adhesive in step 2, the ratio of acetone:xylene:butyl acetate:acrylic resin is 1:2:1:0.

2.

6. The method for laser orthopedic brazing of vibration-damping bosses of aircraft engine fan rotor blades according to claim 1 is characterized by: The rectangular flat-top laser spot size in step 4 is 5×2-12×3 mm.

7. The method for laser orthopedic brazing of vibration-damping bosses of fan rotor blades of aircraft engines according to claim 1 is characterized by: The laser on time in step 4 is 5-10s.