Method for repairing complex thin-walled titanium alloy aero-engine casing
By combining laser additive deposition equipment with argon arc welding, a segmented repair method was developed, which solved the problem of repairing large-area damage to complex thin-walled titanium alloy casings. This method achieved low-deformation, high-quality, and high-efficiency repair, filling a technological gap in this type of part.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU ENGINE GROUP
- Filing Date
- 2026-05-18
- Publication Date
- 2026-07-31
AI Technical Summary
Existing repair methods cannot effectively solve the problem of large-area damage to complex thin-walled titanium alloy aero-engine casings, resulting in large welding deformation in the repair area, collapse of the thin-walled area, high residual stress, and insufficient accessibility of the laser deposition powder delivery head, leading to low repair efficiency.
A repair method combining laser additive deposition equipment and argon arc welding is adopted. Through segmented repair process and variable power parameter control, combined with low temperature heat treatment, high-quality repair of complex thin-walled titanium alloy casings is achieved.
It has achieved low deformation and high-quality repair of complex thin-walled ZTA15 titanium alloy aircraft casings, solved problems such as insufficient accessibility of laser deposition powder feeding head and large welding deformation, and improved repair efficiency.
Smart Images
Figure CN122480338A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of casing repair methods, and particularly relates to a repair method for a complex thin-walled titanium alloy aero-engine casing. Background Technology
[0002] The engine casing of an aircraft engine has a complex, thin-walled structure. During machining, improper selection of reference surfaces and incorrect operation often lead to large-area damage, forcing the casing to be scrapped. However, engine casings are extremely expensive, have long machining cycles, and are prone to errors. If a casing is scrapped due to localized damage, it will result in significant economic losses and extended delivery times. Therefore, there is an urgent need to develop a new repair technology for complex, thin-walled titanium alloy engine casings.
[0003] The manufacturer attempted repairs using conventional TIG welding, which offers advantages such as high flexibility, low cost, and high efficiency. However, its high heat input leads to significant welding deformation in the repair area, collapse in thin-walled regions, and high residual stress, making it unsuitable for repairing large-area damage to thin-walled casings. In contrast, laser direct deposition (LDD) is a novel component repair and remanufacturing technology. This technology boasts significant advantages such as low heat input, narrow heat-affected zone, low residual stress, and high interfacial bonding strength, making it particularly suitable for repairing large-area damage to thin-walled critical components. However, due to the technical requirements for repair forming and interference from complex component structures, the reachability of the laser deposition powder feeder is insufficient. Furthermore, existing laser additive deposition processes, while providing overall repair forming, are prone to burn-through in thinner areas and cannot eliminate residual stress, leading to overall component deformation.
[0004] In summary, existing repair methods are inefficient in repairing the casing. Summary of the Invention
[0005] In view of this, the repair method for complex thin-walled titanium alloy aero-engine casing of the present invention solves the technical problems of large deformation and low efficiency of existing repair methods for repairing casings.
[0006] A repair method for complex thin-walled titanium alloy aero-engine casings is disclosed. This method is applicable to laser additive deposition equipment and argon arc welding processes for repairing the mounting edge of ZTA15 titanium alloy thin-walled casings to a standard thickness (2-4 mm). (Generally, the top view of the area to be repaired is annular, or approximately annular, closed, or open, etc.). The standard thickness is divided into a first thickness (1-1.5 mm) and a second thickness (1-2.5 mm, overlapping with the first thickness). The repair method includes...
[0007] S1: The area to be repaired undergoes initial processing, and the repair materials for both the laser additive deposition equipment and the argon arc welding process are made of TC4 material. TC4 and ZTA15 both belong to the "Ti-Al-V" series of titanium alloys and have similar physical and chemical properties. During welding, they can form a dense metallurgical bond, effectively avoiding cracks caused by material differences. They can achieve precise heat input control, which helps to reduce welding stress and the range of the heat-affected zone.
[0008] S2: The area to be repaired is divided into multiple arc-shaped repair areas. Arc-shaped repair areas within the area to be repaired that are less than a first preset thickness (for example, arc-shaped repair areas with a thickness of less than 0.5 mm are marked) are marked. Preferably, the arc-shaped repair areas with a thickness of less than 0.5 mm are sorted, and the arc-shaped repair area with the smallest thickness is repaired first. This maximizes the elimination of residual stress after repair and balances the stress during the repair process. S3: Any marked arc-shaped repair area is repaired using a laser deposition process with the first power parameter, employing a layered, symmetrical repair method. S31: When repairing the currently marked arc-shaped repair area, first repair it to the first thickness (1mm), then repair the arc-shaped repair area symmetrical to it to the first thickness, and so on, to complete the repair of all marked arc-shaped repair areas. Preferably, the repair is performed in order of increasing thickness. For example, if the thickness is 0.4mm, 0.45mm and 0.5mm, first repair the 0.4mm arc-shaped repair area, and then repair the arc-shaped repair area symmetrical to the 0.4mm. After that, repair the 0.45mm arc-shaped repair area in the same way. S32: Select one of the unmarked and unrepaired arc-shaped repair areas, repair it to the first thickness first, and then repair the arc-shaped repair area symmetrical to it to the first thickness. S4: The arc-shaped repair area to the first thickness is repaired using a laser deposition process with the second power parameter, and all arc-shaped repair areas to the second thickness (the total thickness of the repair is completed to 2mm, i.e., repairing another 1mm) is completed using a layered and symmetrical repair method, and the parameter value of the second power parameter is greater than the parameter value of the first power parameter.
[0009] If the laser head of the laser additive deposition equipment is obstructed by a local component of the housing during repair in S3 or S4, an argon arc welding process is used to repair the corresponding thickness. The purpose of distinguishing between the second power parameter and the first power parameter is to avoid directly welding through thinner areas using the second power parameter, allowing for more precise repair and improved efficiency.
[0010] Preferably or optionally, for the repair of the mounting edge of the casing with a high precision level, the thickness value of the second thickness is set to be greater than the thickness value of the first thickness; and / or, both the first thickness and the second thickness are divided into multiple thickness layers (e.g., 1mm is divided into 0.5mm and 0.5mm repairs, each 0.5mm repair is performed symmetrically, and the next 0.5mm repair is completed after each 0.5mm repair), and argon gas is continuously supplied for anti-oxidation protection during the repair process; and / or, the argon arc welding process parameter values are different for the first thickness and the second thickness repair.
[0011] Preferably or optionally, each thickness layer is the same. After each thickness layer is repaired, when the temperature is below 50 ℃, residual stress is eliminated once before the next thickness layer is repaired. In this way, the overall process adopts the method of eliminating residual stress multiple times, so that the formed blade is less affected by stress.
[0012] Preferred or optional, the casing is mounted on a base, wherein the top surface of the base has a groove, the casing is placed in the groove, and multiple fan-shaped blocks are placed continuously in the groove to press against the inner side of the casing. The inner side of the casing is pressed against by a pressure plate installed on the top surface of the base. This method can adapt to the current mainstream segmented repair method and avoid the situation where the residual stress after one-time molding repair causes deformation of the thin-walled mounting edge.
[0013] Preferably, or optionally, the S1 type laser additive deposition equipment uses TC4 powder, and the argon arc welding process uses TC4 welding wire. The powder has a particle size of 53–150 μm. Before use, the powder needs to be vacuum dried at 120 °C for 30 min and then oven cooled to room temperature. The diameter of the welding wire is 0.8 to 1 mm.
[0014] Preferably or optionally, the casing after the S3 repair process undergoes low-temperature heat treatment, wherein, The furnace is heated to 300-400 ℃ and held at that temperature for 6 hours.
[0015] Preferably or optionally, the casing after the S4 repair process undergoes high-temperature heat treatment, wherein, The furnace is heated to 500-650℃ and held at that temperature for 2 hours before being cooled.
[0016] Preferably, or optionally, after repair by the S4 repair process, non-destructive testing and machining processes are carried out in sequence.
[0017] Preferred or optional, the first power parameters are: laser power 200 W, cladding head moving speed 8 mm / s, powder feeding speed 0.4 rap, powder feeding gas flow rate 4 L / min, protective gas flow rate 13 L / min, and overlap rate 50%.
[0018] Preferred or optional, the first power parameters are: laser power 300 W, cladding head moving speed 8 mm / s, powder feeding speed 0.4 rap, powder feeding gas flow rate 4 L / min, protective gas flow rate 15 L / min, and overlap rate 50%.
[0019] The beneficial effects of the present invention are as follows: This method effectively solves the problems of large welding deformation, thin-walled collapse, and high residual stress in the repair area during existing TIG welding repair of complex thin-walled ZTA15 titanium alloy casings, as well as the problem of insufficient reachability of the laser deposition powder feeder. It achieves low-deformation, high-quality repair of complex thin-walled ZTA15 titanium alloy aerospace casings. The variable-power, layered, segmented, and symmetrical laser deposition repair enables high-quality and efficient repair. When the repair area thickness is less than 1 mm, low-power parameters prevent weld leaks in thin-walled parts; when the repair area thickness is greater than 1 mm, high-power parameters improve deposition efficiency. Segmented symmetrical repair ensures balanced residual stress distribution; intermediate low-temperature heat treatment reduces residual stress without affecting the microstructure, thus guaranteeing small deformation, high-quality, and high-efficiency repair of complex thin-walled casings. This repair method is specifically designed for the repair of large-area damage to complex thin-walled titanium alloy casings, filling the technological gap in direct laser deposition repair of such parts. It can be widely applied to the repair of large-area damage to complex thin-walled titanium alloy casings in various aero-engines. Attached Figure Description
[0020] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the casing of the present invention mounted on the base; Figure 3 This is a schematic diagram illustrating the segmented deposition sequence principle of an embodiment of the present invention; Figure 4 This is a phase diagram of laser-deposited gold according to an embodiment of the present invention. Detailed Implementation
[0022] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.
[0023] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure 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 this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0024] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.
[0025] like Figures 1 to 4 The tooling shown is designed to gradually repair the entire installation edge using a segmented repair process. This overcomes the problems of large welding deformation, collapse of the thin-walled area, and high residual stress in the repair area during the existing argon arc welding repair of large-area damage to complex thin-walled titanium alloy casings. It also solves the problem of insufficient reachability of the laser deposition powder delivery head. This provides a composite repair method of laser direct deposition and argon arc welding for large-area damage to complex thin-walled ZTA15 titanium alloy aero-engine casings. The goal is to achieve low deformation and high-quality repair of complex thin-walled ZTA15 titanium alloy aero-engine casings.
[0026] Example 1 (1) Selection of repair powder and welding wire; composite repair using laser deposition equipment and argon arc welding equipment. The TC4 powder used for repair was prepared according to the specifications in "HB 20514-2018 Powder Specification for Laser Direct Deposition Repair of Titanium Alloy Components". The powder particle size was 53–150 μm. The powder needed to be vacuum dried before use: temperature 120 ℃, holding time 30 min, furnace cooled to room temperature. TC4 welding wire with a diameter of 0.8–1 mm was used. Both the argon arc welding wire and the laser-integrated powder were made of TC4 material. (2) Repair of the areas to be repaired on the casing, the surface of the deposited repair area, and the transition area; Before repair, use a hand-held polishing gun to clean the surface, remove surface dirt, smooth the transition area between the damaged area and the substrate, and finally clean with alcohol.
[0027] (3) Measurements taken before repair; Before the repair, the dimensions of the area to be repaired are measured using vernier calipers to determine the required deposition thickness and mark it, for example, a thickness of less than 1 mm is marked.
[0028] (4) Modular easy-to-disassemble anti-deformation tooling installation and nozzle argon gas protection tooling clamping; argon gas is blown in the repair area. During deposition repair, argon arc welding and cooling are also blown. The purpose is to prevent the casing in the deposition and welding area from contacting air and oxidizing. For example, the groove + jet pipe combination method.
[0029] The area to be repaired was secured and clamped using anti-deformation tooling, and then protected with argon gas oxidation. (5) Variable power welding and deposition methods are adopted: for thin damage, low power is used to repair 1mm, and then the power is increased for repair. The method is symmetrical segmentation, and each layer is treated at low temperature to ensure that there is no deformation or penetration when repairing with high power. Argon arc welding is used to solve the interference problem caused by the parts to the laser deposition nozzle.
[0030] When the thickness of the repair area is less than 1 mm, a low-power parameter segmented and layered symmetrical laser deposition repair method (stress distribution control) is adopted, combined with an argon arc welding edge-locking composite repair method. Individual anti-deformation tooling modules interfering with the repair of the thin-walled casing are locally removed, and the cladding head angle is adjusted to maximize cladding head accessibility. Low-power laser deposition is used to deposit layers in the repair area. The parameters for low-power laser deposition repair are: laser power 200~250 W, cladding head moving speed 8~12 mm / s, powder feed rate 0.3~0.5 rap, powder feed gas flow rate 3~5 L / min, shielding gas flow rate 10~15 L / min, and overlap rate 40-50%. Simultaneously, after each layer deposition, a thermometer is used to measure the temperature near the deposition layer. The second layer deposition can only be performed when the temperature is below 50℃, until a layer of 1 mm is deposited. Repair is stopped when the thickness reaches mm; a single anti-deformation tooling module is installed and fixed at that location. Then, following this process, the damaged area on the opposite side is repaired to achieve symmetrical repair. Through segmented symmetrical repair, the laser deposition repair of all areas within that thickness range is completed. The segmented symmetrical repair sequence is as follows: Figure 3 As shown.
[0031] The area on the casing that interferes with the laser deposition powder feed head is repaired by argon arc welding. At this time, the argon arc welding is still carried out by layering, symmetry and segmentation. For the interference at the powder feeding head, argon arc welding was used for repair. The welding repair process parameters were as follows: welding current of 40-50 A, welding voltage of 8-11 V, argon flow rate of 15 L / min, tungsten electrode diameter of Φ1.6 mm, back protection was used during welding, and the shielding gas flow rate was 10-30 L / min. The repair was also carried out in segments and symmetrically, and a good overlap was formed with the laser deposition area.
[0032] Areas that cannot be repaired by laser are repaired using argon arc welding.
[0033] (6) Low-temperature heat treatment; The repaired engine casing undergoes overall low-temperature heat treatment to eliminate welding stress within the repaired areas. The heat treatment process involves heating in the furnace, holding at 300-400°C for 6 hours, followed by furnace cooling, with the anti-deformation modular tooling remaining in place. The purpose is to eliminate residual stress and prevent further deformation of the repaired structure, whereas traditional methods employ high-temperature repairs.
[0034] (7) The target repair thickness is 2mm. Step 5 completes the repair of 1mm thickness. The remaining 1mm is repaired using high-power laser deposition: the segmented, symmetrical, and layered method is still used. High-power repair increases deposition efficiency and reduces time consumption. When the thickness of the repair area is greater than 1mm, high-power parameter segmented and layered symmetrical laser deposition is used, combined with argon arc welding edge locking composite repair method for the second repair; the single anti-deformation tooling module with interference at the thin-walled casing to be repaired is removed locally, and the laser power is increased to perform the second layer-by-layer deposition on the area to be repaired. The parameters for laser deposition repair with increased power are: laser power 250~400W, cladding head moving speed 8~12 mm / s, powder feeding rate 0.3~0.5 rap, powder feeding gas flow rate 3~5 L / min, protective gas flow rate 10~15 L / min, overlap rate 40-50%; after each layer deposition, it is cooled to below 50℃ before the second layer deposition is performed until the part is deposited to the required machining size. The single anti-deformation tooling module at this part is installed and fixed; then, following this process, the following is used. Figure 3The laser deposition portion of the part was repaired using a segmented symmetrical repair sequence. For the interference at the powder feeding head, argon arc welding was used for supplementary repair. The welding repair process parameters were: welding current of 40-50 A, welding voltage of 8-11 V, argon flow rate of 15 L / min, tungsten electrode diameter of Φ1.6 mm, and back protection was used during welding with a shielding gas flow rate of 10-30 L / min. Similarly, the tooling module was partially disassembled for segmented symmetrical repair, and a good overlap was formed with the laser deposition area.
[0035] conventional methods (8) Overall high-temperature heat treatment; The weld repair sites on the engine casing undergo post-weld high-temperature stress-relieving heat treatment to remove internal welding stress. The heat treatment process is as follows: heating in the furnace, holding at 500~650℃ for 2 hours, followed by furnace cooling; the anti-deformation fixtures are not removed during the heat treatment process.
[0036] (9) Non-destructive testing of repaired parts; Fluorescent flaw detection and X-ray inspection were used to perform non-destructive testing on the weld repair positions of the complex thin-walled ZTA15 titanium alloy aero-engine casing. If there were no cracks or lack of fusion defects, clamp repair and argon arc welding were used to repair the welds until there were no cracks or lack of fusion defects.
[0037] (10) After repair, the dimensions are machined. The weld repair area is machined using a machine tool and the weld repair position is machined to the required dimensions.
[0038] Example 2 Taking a certain type of engine casing as an example, the repair of circumferential over-cut damage on the mounting edge of the ZTA15 titanium alloy complex thin-walled casing is as follows: (1) Select TC4 powder for laser deposition repair. The powder particle size is 53-150 μm. Before use, the powder is vacuum dried in a vacuum drying oven at 120 ℃ for 30 min and then cooled to room temperature. The argon arc welding wire is TC4 wire with a diameter of 0.8-1 mm.
[0039] (2) Before repair, use a hand-held grinder to grind the circumferential area to be repaired, and at the same time, use clamps to repair the transition area between the damaged area and the substrate to achieve a smooth transition, so as to ensure a good build. Finally, clean with alcohol.
[0040] (3) Before repair, the dimensions of the area to be repaired are measured with calipers. The thinnest part of the area to be repaired is about 0.45 mm, and the average thickness is 0.80 mm, which is 2 mm lower than the specified size of the part. The repair substrate is also relatively thin. Preferably, the equipment is equipped with a camera and a display screen to capture the fan-shaped protrusions after the marking and numbering.
[0041] (4) For the circumferential overcut damage of the casing mounting edge, install easy-to-remove anti-deformation tooling including fan-shaped protrusions along the mounting edge to prevent deformation of the casing during repair. The repair area is segmented by installing the fan-shaped protrusions. The segmented easy-to-remove tooling facilitates symmetrical segmented and layered welding. The powder feeding cladding head is protected by argon gas flow tooling to prevent alloy oxidation during the repair process.
[0042] (5) During the repair, first repair the area with a thickness of less than 1 mm. Remove the single anti-deformation tooling module that interferes with the repair area of the thin-walled casing. Adjust the angle of the cladding head to maximize the reachability of the cladding head. Use low-power laser deposition repair parameters for deposition: laser power 200 W, cladding head moving speed 8 mm / s, powder feeding rate 0.4 rap, powder feeding gas flow rate 4 L / min, protective gas flow rate 13 L / min, overlap rate 50%. After each layer of deposition, wait for the repair area to cool down to a temperature below 50 ℃ before starting the second layer of deposition. Repeat this process until the thickness of 1 mm is reached and then stop the repair. After the area is repaired, install and fix the single anti-deformation tooling module in that area.
[0043] (6) according to Figure 3 The repair sequence shown involves rotating the part 180° and repairing the position according to the procedure in (5), performing symmetrical repair. Figure 3 The area marked 1 is 0.4mm (after repair, the area marked 2 is symmetrical to the area marked 1), and the area marked 3 is 0.45mm (the area marked 4 is symmetrical to the area marked 3). After the two thinnest areas are repaired, the remaining marked areas are repaired in a symmetrical and layered manner. (7) Press again Figure 3 The repair sequence shown is to rotate the part by 90° and then repair the repair area according to the process in (5).
[0044] (8) Press again Figure 3 The repair sequence shown involves rotating the part 180° and performing symmetrical repairs on the positions symmetrical to the repair area in (7) according to the process in (5).
[0045] (9) Repair the area to be repaired by shifting the repair area one anti-deformation module to the right in (5), and then repeat steps (6), (7), and (8) until all repair areas are repaired.
[0046] (10) For the interference of the powder feeding head, argon arc welding is used for repair. The welding repair process parameters are: welding current is 45 A, welding voltage is 10 V, argon flow rate is 15 L / min, tungsten electrode diameter is Φ1.6 mm, back argon protection is used during welding, and the protective gas flow rate is 20 L / min. The same segmented symmetrical repair is adopted, and a good overlap is formed with the laser deposition area.
[0047] (11) After the engine casing is repaired to a thickness of 1 mm, the whole body is subjected to low temperature heat treatment to eliminate residual stress. The heat treatment process is as follows: the temperature is raised with the furnace, held at 300 ℃ for 6 hours, and then cooled in the furnace. During the heat treatment, the anti-deformation modular tooling is not disassembled to prevent the parts from deforming.
[0048] (12) When the thickness of the repair area is greater than 1 mm, the laser power parameters are increased to deposit the repair area layer by layer. The parameters for laser deposition repair are: laser power 300 W, cladding head moving speed 8 mm / s, powder feeding rate 0.4 rap, powder feeding gas flow rate 4 L / min, protective gas flow rate 15 L / min, and overlap rate 50%. After each layer is deposited, the repair area is allowed to cool down to below 50℃ before the second layer is deposited. This process is repeated until the deposited area is 0.3 mm larger than the final size of the part. Then, the repair is stopped, and a single anti-deformation tooling module is installed and fixed in that area.
[0049] (13) Perform symmetrical cyclic repair in the same manner as steps (5)-(9).
[0050] (14) For the interference of the powder feeding head, argon arc welding is used for supplementary repair. The welding repair process parameters and segmented symmetrical repair method are the same as in step 10 to ensure that the argon arc welding area and the laser deposition area form a good overlap.
[0051] (8) The engine casing after repair is subjected to overall high-temperature stress relief heat treatment. The heat treatment process is as follows: the temperature is raised with the furnace, held at 500℃ for 2 hours, and then cooled in the furnace. The anti-deformation fixtures are not removed during the heat treatment process.
[0052] (9) Fluorescent flaw detection and X-ray inspection were used to inspect the welding positions of the complex thin-walled aero-engine casing of ZTA15 titanium alloy. After discovering cracks and non-fusion defects, argon arc welding was performed to repair the welds, ultimately achieving the goal of no cracks and no non-fusion defects.
[0053] (10) Use a machine tool to process the welding area and process the welding position to the required size.
[0054] Simultaneously, laser deposition tests were conducted on specimens made of the same material under the same heat treatment conditions. The microstructure of the laser-deposited specimens was as follows: Figure 4 As shown, after repair using this method, the overall casing exhibits good microstructure formation, with no porosity or unfused areas. Tensile tests on specimens prepared using the same process show a room temperature tensile strength of 760-828 MPa, exceeding the part's performance requirement of 752 MPa. The specimens also demonstrate creep resistance at 300℃ and 300 MPa for more than the required 200 hours. This method effectively repairs large-scale damage defects in casing components, offering advantages such as crack-free repair, no unfused areas, minimal deformation, ability to repair dissimilar materials, and satisfactory mechanical properties.
[0055] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A repair method for complex thin-walled titanium alloy aero-engine casings, applicable to laser additive deposition equipment and combined with argon arc welding process, for repairing the standard thickness area of the mounting edge of a ZTA15 titanium alloy thin-walled casing, characterized in that... The standard thickness is divided into a first thickness and a second thickness, and the repair method includes... S1: The area to be repaired undergoes initial processing, and the repair materials for both the laser additive deposition equipment and the argon arc welding process are made of TC4 material; S2: The area to be repaired is divided into multiple arc-shaped repair areas, and the arc-shaped repair areas within the area to be repaired that are smaller than the first preset thickness are marked; S3: Any marked arc-shaped repair area is repaired using a laser deposition process with the first power parameter, employing a layered, symmetrical repair method. S31: When repairing the currently marked arc-shaped repair area, first repair it to the first thickness, then repair the arc-shaped repair area symmetrical to it to the first thickness, and so on to complete the repair of all marked arc-shaped repair areas. S32: Select one of the unmarked and unrepaired arc-shaped repair areas, repair it to the first thickness first, and then repair the arc-shaped repair area symmetrical to it to the first thickness. S4: The arc-shaped repair area up to the first thickness is repaired using a laser deposition process with a second power parameter, and all arc-shaped repair areas up to the second thickness are repaired using the aforementioned layered and symmetrical repair method, with the parameter value of the second power parameter being greater than the parameter value of the first power parameter. If the laser head of the laser additive deposition equipment is blocked by a local part of the casing during repair in S3 or S4, argon arc welding is used to repair the corresponding thickness.
2. The repair method according to claim 1, characterized in that, The thickness value of the second thickness is greater than the thickness value of the first thickness; and / or, both the first thickness and the second thickness are divided into multiple thickness layers, and argon gas is continuously supplied during the repair process for anti-oxidation protection; And / or, the TIG welding process parameter values are different when repairing the first thickness and the second thickness.
3. The repair method of claim 2, wherein Each of the aforementioned thickness layers has the same thickness, and after each thickness layer is repaired, the next thickness layer is repaired only when the temperature is below 50 ℃.
4. The repair method of claim 1, wherein The casing is mounted on a base, the top surface of which has a groove. The casing is placed in the groove, and multiple sector-shaped blocks are placed in the groove to press against the inner side of the casing. The inner side of the casing is pressed against by a pressure plate mounted on the top surface of the base.
5. The method of repairing according to claim 1, wherein, The S1 type laser additive deposition equipment uses TC4 powder, and the argon arc welding process uses TC4 welding wire. The powder has a particle size of 53–150 μm. Before use, the powder needs to be vacuum dried at 120 °C for 30 min and then oven cooled to room temperature. The diameter of the welding wire is 0.8 to 1 mm.
6. The method of repairing according to claim 1, wherein, The casing, after the S3 repair process, undergoes low-temperature heat treatment, in which... The furnace is heated to 300-400 ℃ and held at that temperature for 6 hours.
7. The repair method according to claim 1, characterized in that, The casing, after the S4 repair process, undergoes high-temperature heat treatment, among which... The furnace is heated to 500-650℃ and held at that temperature for 2 hours before being cooled.
8. The repair method according to claim 1, characterized in that, After being repaired using the S4 repair process, the product undergoes non-destructive testing and machining processes in sequence.
9. The repair method according to claim 1, characterized in that, The first power parameter is The laser power is 200 W, the cladding head moving speed is 8 mm / s, the powder feeding rate is 0.4 rap, the powder feeding gas flow rate is 4 L / min, the protective gas flow rate is 13 L / min, and the overlap rate is 50%.
10. The repair method according to claim 1, characterized in that, The first power parameters are: laser power 300 W, cladding head moving speed 8 mm / s, powder feeding speed 0.4 rap, powder feeding gas flow rate 4 L / min, protective gas flow rate 15 L / min, and overlap rate 50%.