Composite additive repair method for intermediate casing support plate sidewall damage

Abstract

The composite additive repair method for the damaged side wall of the intermediate case support plate of the application comprises the following steps: determining the to-be-repaired area of the intermediate case, pretreating burrs and dirt, making a gasket according to the shape of the to-be-repaired area, and injecting a molten pool liquid of laser deposition additive into the to-be-repaired area; an arc-shaped blocking step is formed by arc additive at the junction of the to-be-repaired area and the outer ring surface of the intermediate case; when the molten pool liquid reaches a preset size thickness, the intermediate case is flipped and horizontally rotated to a preset angle with the horizontal direction by the all-around mobile device, and the to-be-repaired area is located at the highest point; the laser deposition additive process is used for repair, and thermal stress relief is performed after repair. The method can improve the repair efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of remanufacturing technology for key components of aero-engines, and particularly relates to a composite additive repair method for sidewall damage of intermediate casing support plate. Background Technology

[0002] There are many casing-type parts in aero engines, such as the inlet casing, low-pressure compressor casing, high-pressure compressor casing, combustion chamber casing, turbine casing, and afterburner casing. Among them, the integral annular intermediate casing with hollow rectifier support plate, as a core load-bearing component of aero engines, has a high-precision thin-walled integrated structure of inner ring-support plate-outer ring. In milling, due to the complex spatial angles of the support plate (typically composed of 8-20 sets of circumferentially distributed support plates), the milling cutter is prone to overcutting and damaging the substrate, especially in intermediate housings made of Ti 175 titanium alloy. When finishing milling to the final dimensions, overcutting damage occurs to the inner ring of the support plate during tool retraction, directly milling through the inner ring. Moreover, the damaged area is large, typically with a maximum width of 47.2392 mm and a maximum depth of 55.6611 mm (from the C reference plane). The maximum depth of the penetrated wall is 44.9299 mm (from the C reference plane), and the maximum width is 35.5718 mm. Since the part dimensions have been finished and the space of the damaged area of ​​the inner ring of the support plate is small, in order to accurately control the deformation of the part during repair and prevent dimensional deviations, and because a single repair method cannot complete the full-area repair of the damaged area of ​​the part due to spatial interference, a large-scale repair is not possible.

[0003] For the repair of thin-walled parts with large damage, the traditional method uses a single argon arc welding repair technology. Due to the high heat input, the heat-affected zone of titanium alloy materials coarsens and the part is deformed. Thermal spraying repair technology has low bonding strength and cannot meet the strength requirements of the repair area. Moreover, the narrow gaps in the damaged area make it difficult to complete the full-size repair of the damage. Therefore, the traditional method has low repair efficiency.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a composite additive repair method for damage to the sidewall of an intermediate casing support plate, solving the technical problem of low repair efficiency in traditional methods. The technical solution of this invention has many beneficial effects, as described below:

[0006] A composite additive repair method for sidewall damage of an intermediate casing support plate, the composite additive repair method comprising:

[0007] S1: Identify the repair area of ​​the intermediate casing and perform pre-treatment of burrs and dirt;

[0008] S2: A gasket is made according to the shape of the area to be repaired. The gasket is formed with an arc-shaped step. The area to be repaired is welded to the arc-shaped step of the gasket by arc welding.

[0009] S3: After welding, the intermediate housing is installed on the universal mobile device. The universal mobile device can drive the intermediate housing to rotate horizontally and flip, and inject the laser deposition additive molten pool into the area to be repaired.

[0010] S4: At the junction of the area to be repaired and the outer ring surface of the intermediate casing, an arc-shaped blocking step is formed by electric arc additive manufacturing. The arc-shaped blocking step is used to prevent the molten pool from flowing out or overflowing.

[0011] S5: When the molten pool reaches the preset thickness, the intermediate casing is flipped and rotated horizontally by the omnidirectional mobile device to form a preset angle with the horizontal direction, and the area to be repaired is placed at the highest point. Laser deposition additive manufacturing process is used for repair, and thermal stress is eliminated after repair.

[0012] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0013] The method of this invention adopts a composite repair method of "laser deposition additive manufacturing + electric arc additive manufacturing", which realizes high-quality repair of intermediate casing with high accessibility and low deformation. This method reduces repair costs by about 98% and shortens the repair cycle by about 88%, and has been successfully applied to equipment engines. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of the process of the present invention;

[0016] Figure 2 This is a schematic diagram of an arched staircase.

[0017] Figure 3 This is a schematic diagram of the microstructure of the substrate area after repair.

[0018] Figure 4 This is a schematic diagram of the microstructure of the heat-affected zone after repair.

[0019] Figure 5 This is a schematic diagram of the microstructure of the laser and arc composite additive region after repair. Detailed Implementation

[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that aspects can be practiced without these specific details. To enable those skilled in the art to better understand the invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0022] like Figures 1 to 5 The method described herein is a composite additive repair method for damage to the sidewall of the intermediate casing support plate. The composite additive repair method includes...

[0023] S1: Determine the area to be repaired in the intermediate casing and perform pretreatment of burrs and dirt. Specifically, the pretreatment includes machining and fitting the area to be repaired, removing the burrs from the inner ring sidewall of the intermediate casing, ultrasonically cleaning the area to be repaired, and removing oil, impurities and coolant. After cleaning, the area is dried at a temperature of 110-150℃ for a drying time of ≥2 hours.

[0024] S2: A gasket is fabricated according to the shape of the area to be repaired. The gasket is formed with curved steps. The area to be repaired is welded to the curved steps of the gasket using arc welding. Specifically...

[0025] The curved step includes an irregular curved step, a first curved part and a second curved part. The thickness of the second curved part is greater than that of the first curved part, and the first and second curved parts are connected by the curved step. The width and material of the first and second curved parts are the same. The curved step can fit the inner ring surface of the intermediate casing and its position corresponds to the area to be repaired.

[0026] S3: After welding, the intermediate housing is installed on the Wanxiang mobile device. The Wanxiang mobile device can drive the intermediate housing to rotate and flip horizontally, and inject the laser deposition additive molten pool into the area to be repaired. The molten pool adopts the arc additive manufacturing process. The arc additive manufacturing process parameters are: current 60-100A, welding wire TC4 diameter 1.0mm, welding torch argon flow rate 15-20 liters / minute, tail cover argon flow rate 10-15 liters / minute, argon gas pre-entry time ≥60 seconds, and argon gas de-entry time ≥30 seconds.

[0027] S4: At the junction of the area to be repaired and the outer ring surface of the intermediate casing, an arc-shaped blocking step is formed by arc additive manufacturing. The arc-shaped blocking step is used to prevent the molten pool from flowing out or overflowing. Preferably, the thickness of the arc-shaped blocking step is 3mm and the width is 5mm, which can hold the molten pool and prevent the molten pool from overflowing due to gravity or expansion force.

[0028] S5: When the molten pool reaches a preset thickness, such as a solidified molten pool thickness greater than 3mm and a width greater than 5mm, the intermediate casing is flipped and rotated horizontally using a multi-functional moving unit to a preset angle with the horizontal direction, for example, 60°, with the area to be repaired positioned at the highest point. Laser deposition additive manufacturing is then used for repair. After repair, thermal stress is relieved. Specifically...

[0029] In the area to be repaired, the laser nozzle is used to repair the area. The intermediate casing is flipped and rotated horizontally to a 60° angle with the horizontal direction by the universal mobile device. The parameters of the laser deposition additive process are: power gradient control of 550W for the bottom layer, 450W for the middle and surface layers, interlayer temperature ≤150℃, powder feeding parameters of TC4 powder with a particle size of 53-150μm, and powder feeding speed of 0.3-0.5 rpm.

[0030] In the area to be repaired, the arc additive manufacturing process is used to repair areas that cannot be repaired using laser nozzles.

[0031] Thermal stress relief includes stress-relieving heat treatment of the deformed area (no more than 0.3 mm) on the inner circumferential surface of the intermediate casing. The temperature is 500±10℃, held for 230-240 min, vacuum degree ≤0.067 Pa, and heating time ≥120 min. Holding at 350-400℃ during the heating process is prohibited. Because the repair method combines laser deposition additive manufacturing and arc additive manufacturing, significant localized stress is easily generated inside the casing after repair, thus requiring thermal stress relief.

[0032] Furthermore, the laser deposition additive manufacturing system is configured with: a ring-shaped coaxial powder feeding laser head, a 3000W fiber laser, a synchronous preheating powder feeding device, and high-purity argon gas protection.

[0033] S6: Test results: Fluorescent penetrant testing showed no cracks; X-ray testing showed no cracks, lack of fusion, flaky or sharp-angled inclusions or other defects in the repaired area and its heat-affected zone; the internal pores met the requirements. Post-processing: CNC precision milling of the repaired area.

[0034] In one specific embodiment, the intermediate casing is made of Ti 175 titanium alloy. The maximum width of the area to be repaired is 48 mm, and the maximum depth from the C-reference plane is 56 mm. The method of this invention is for repairing large areas. The intermediate casing after the repair process of "laser deposition additive manufacturing + arc additive manufacturing" has a display area that includes a matrix area + heat-affected zone + laser deposition additive manufacturing area + arc additive manufacturing area. The bonding surface between the deposited layer and the matrix, as well as the metallurgical bonding between the laser deposition and arc additive manufacturing areas, are good, without cracks, lack of fusion, or other defects. The internal pore size is approximately 0.06 mm, which meets the requirements. The matrix area has a bimodal structure, with the primary α phase uniformly distributed in the β-transformed matrix. The primary α phase in the structure is equiaxed, elliptical, or elongated, such as... Figure 3 As shown, the microstructure of the heat-affected zone underwent significant changes. Compared to the matrix, the α phase was smaller in size and less abundant. Near the boundary of the fusion zone, phase boundary blurring occurred, as shown in the figure. Figure 4 As shown, the laser and arc composite deposition additive region is deposited through a multi-pass, multi-layer method. The deposition region consists of β-columnar crystals, which have epitaxial growth characteristics. During the laser deposition and arc additive multi-layer deposition process, primary β-columnar crystals are formed through nucleation. The solidification process proceeds with the advancement of the solid-liquid interface. During this process, the liquid metal and its solid substrate remain in contact, and the structure exhibits typical continuous growth characteristics. The β-columnar crystals continue to grow at the top of the molten pool of the previous layer, continuing to grow from the previous layer of β-columnar crystals, and penetrating multiple laser and arc deposition layers. Therefore, the method of the present invention can meet the design requirements after repair.

[0035] The repair was tested, and the results are as follows:

[0036] The average room temperature tensile strength reaches 1135 MPa (design standard: 1050 MPa); the average high temperature tensile strength at 400℃ reaches 852 MPa (design standard: 750 MPa); and the average low cyclic strain fatigue (250℃, stress control, stress ratio -1, frequency 0.5-5 Hz, maximum stress amplitude 450 MPa, sine wave or triangular wave) life reaches 26515 cycles (design standard: 10000 cycles).

[0037] The product provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from the principles of the invention, and these improvements and modifications also fall within the protection scope of the invention claims.

Claims

1. A composite additive repair method for sidewall damage of an intermediate casing support plate, characterized in that, The composite additive repair method includes, S1: Identify the repair area of ​​the intermediate casing and perform pre-treatment of burrs and dirt; S2: A gasket is made according to the shape of the area to be repaired. The gasket is formed with an arc-shaped step. The area to be repaired is welded to the arc-shaped step of the gasket by arc welding. The arc-shaped step includes an irregular arc-shaped step, a first arc-shaped part and a second arc-shaped part. The thickness of the second arc-shaped part is greater than that of the first arc-shaped part. The first arc-shaped part and the second arc-shaped part are connected by the arc-shaped step. The width and material of the first arc-shaped part and the second arc-shaped part are the same. The arc-shaped step can fit the inner ring surface of the intermediate casing and its position corresponds to the area to be repaired. S3: After welding, the intermediate housing is installed on the universal mobile device. The universal mobile device can drive the intermediate housing to rotate and flip horizontally, and inject the laser deposition additive molten pool into the area to be repaired. S4: At the junction of the area to be repaired and the outer ring surface of the intermediate casing, an arc-shaped blocking step is formed using an electric arc additive manufacturing process. The arc-shaped blocking step is used to prevent the molten pool from flowing out or overflowing. S5: When the molten pool reaches a preset thickness, the intermediate casing is flipped and rotated horizontally by the universal mobile device to form a preset angle with the horizontal direction, and the area to be repaired is at the highest point. Then, laser deposition additive manufacturing process is used for repair, and thermal stress is eliminated after repair.

2. The composite additive repair method according to claim 1, characterized in that, The preprocessing in S1 includes, The area to be repaired is machined and fitted to remove the burrs from the inner ring sidewall of the intermediate casing. Ultrasonic cleaning is used to clean the area to be repaired, removing oil, impurities, and coolant. After cleaning, the area is dried at a temperature of 110-150℃ for ≥2 hours.

3. The composite additive repair method according to claim 1, characterized in that, The intermediate casing is made of Ti175 titanium alloy, and the maximum width of the area to be repaired is 48mm.

4. The composite additive repair method according to claim 1, characterized in that, The arc-shaped blocking step in S4 has a thickness of 3mm and a width of 5mm, which can hold the molten pool and prevent it from overflowing due to gravity or expansion force.

5. The composite additive repair method according to claim 1, characterized in that, The preset size thickness mentioned in S5 is a solidified molten pool thickness greater than 3mm and a width greater than 5mm.

6. The composite additive repair method according to claim 1, characterized in that, Repair using laser deposition additive manufacturing processes includes, Laser deposition additive manufacturing process is used in the area to be repaired within the area that can be repaired using a laser nozzle. The intermediate housing is flipped and rotated horizontally to a 60° angle with the horizontal direction using the omnidirectional mobile device. The parameters of the laser deposition additive manufacturing process are adjusted, with the power gradient control set at 550W for the bottom layer, 450W for the middle and surface layers, interlayer temperature ≤150℃, and powder feeding parameters of TC4 powder with a particle size of 53-150μm and a powder feeding speed of 0.3-0.5 rpm. In the area to be repaired, an electric arc additive manufacturing process is used to repair areas that cannot be repaired using a laser nozzle.

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