Vacuum induction heating local repairing device and method for engine blade

Abstract

The invention provides an engine blade vacuum induction heating local repairing device and method, and belongs to the technical field of aero-engine component repairing, the device comprises at least two sets of portable transformers, and each set of portable transformer comprises two paths of water cooling cables and one path of cooling water pipe; a set of heat compensation induction heater; a set of profiling tool induction heater; the blade profiling heating and heat preservation tool is made of a magnetic conductive (high-temperature-resistant and oxidation-resistant) metal material, an inner cavity of the blade profiling heating and heat preservation tool is matched with the shape of the aero-engine blade to be repaired, and the blade profiling heating and heat preservation tool is wrapped with a high-temperature-resistant heat preservation layer. Through cooperative temperature control of indirect induction heating and root heat compensation of the profiling tool, high-precision and uniform heat treatment of a complex titanium alloy blade repair area is achieved in a vacuum environment, stress is effectively eliminated, the whole piece is prevented from being scrapped, and high reliability, economical efficiency and engineering applicability are achieved at the same time.

Description

Technical Field

[0001] This invention relates to the field of aero-engine component repair technology, and more specifically, to a device and method for local repair of engine blades using vacuum induction heating. Background Technology

[0002] Titanium alloy blades for aero-engines operate under high temperature, high speed, and high stress conditions for extended periods, making them susceptible to wear, chipping, or impact damage from foreign objects. Traditional repair methods typically involve scrapping the entire bladed disk assembly and replacing it with a new one. However, the high cost of titanium alloys, the complex blade structure, and the extremely high precision requirements result in persistently high repair costs. In recent years, with the development of metal additive manufacturing (3D printing) technology, precise repair of locally damaged areas has become possible. However, after repair, stress-relief heat treatment must be performed in a vacuum environment (only on the repaired area) to eliminate residual stress generated during the molten deposition process and prevent the initiation of microcracks, thereby ensuring the mechanical properties and fatigue life of the repaired area.

[0003] However, aero-engine blades have highly complex geometries, exhibiting significant differences in thickness and curvature, and cannot be heat-treated using monolithic heating methods (such as vacuum furnaces). Current technology lacks a method for achieving localized, precise, and coordinated temperature control for irregular titanium alloy blades in a vacuum environment. In particular, it is difficult to stably control the temperature of the repair area within the required range of 400℃–800℃ (with an allowable deviation of ±14℃), resulting in substandard heat treatment effects after repair. This severely restricts the engineering application of additive repair technology in critical hot-end components of aero-engines. Therefore, there is an urgent need to develop a vacuum induction heating local repair device for engine blades to overcome the shortcomings in current practical applications. Summary of the Invention

[0004] The purpose of this invention is to provide a device and method for local repair of engine blades by vacuum induction heating, which aims to solve the problems mentioned in the background art.

[0005] This invention is implemented as follows: a vacuum induction heating local repair device for engine blades, comprising:

[0006] At least two portable transformers, each of which includes two water-cooled cables and one cooling water pipe;

[0007] A set of supplemental heating induction heaters;

[0008] A set of contour-following induction heaters;

[0009] A blade conformal heating and insulation fixture, the blade conformal heating and insulation fixture is made of magnetically conductive metal material, its internal cavity matches the shape of the aero-engine blade to be repaired, and its exterior is covered with a high-temperature resistant insulation layer.

[0010] The contouring tooling induction heater is installed on the blade contouring heating and insulation tooling, and the heat replenishment induction heater and the contouring tooling induction heater are electrically connected to the portable transformer, which is used to achieve heat treatment of the engine blade repair area by indirect induction heating and root heat replenishment in a vacuum environment.

[0011] The supplementary heating induction heater is used to perform local electromagnetic induction heating (supplementary heating) on ​​the connection area between the engine blade root and the engine blade disk.

[0012] The conformal tooling induction heater achieves heating by applying an alternating magnetic field to the blade conformal heating and insulation tooling, thereby generating eddy currents inside the tooling.

[0013] Optionally, the magnetically conductive metal material is selected from molybdenum, nickel, or their alloys.

[0014] Optionally, the high-temperature resistant insulation layer is made of a heat-insulating material with a temperature resistance of not less than 1000℃.

[0015] Optionally, the heat insulation material is ceramic fiber cotton.

[0016] Optionally, there are two portable transformers, which are electrically connected to the heat replenishment induction heater and the contour tooling induction heater respectively.

[0017] Optionally, the target heating temperature range of the blade contour heating and insulation fixture is 400℃–800℃.

[0018] Optionally, it also includes thermocouple temperature measuring points, which are welded to the surface of the engine blades for real-time monitoring of the blade temperature.

[0019] Another object of the present invention is a method for local repair of engine blades using vacuum induction heating, employing the aforementioned engine blade vacuum induction heating local repair device, comprising the following steps:

[0020] Step 1: Place the regular blade contour heating and insulation fixture in a vacuum environment, and apply an alternating magnetic field to it through the induction heater of the contour fixture to generate eddy currents inside the fixture and heat it to the set target temperature within the range of 400℃–800℃. Insulate the temperature to achieve indirect heating of the engine blade; at the same time, weld thermocouple temperature measuring points on the surface of the engine blade to monitor the temperature in real time and provide feedback for regulation.

[0021] Step 2: Simultaneously start the supplementary heating induction heater to perform local electromagnetic induction heating on the connection area between the engine blade root and the engine blade disk, so that the temperature of this area is consistent with the set temperature of the engine blade, thereby achieving precise control and uniformity of the local thermal field of the blade.

[0022] The present invention provides a device and method for local repair of engine blades using vacuum induction heating, which has the following beneficial effects:

[0023] By employing a technical solution that combines indirect induction heating with magnetic metal contouring tooling and temperature control via a root heating sensor, high-precision heat treatment (temperature control accuracy up to ±10℃) is achieved in a vacuum environment for the repair area of ​​titanium alloy blades with complex geometry and uneven thickness. This effectively eliminates residual stress introduced by additive or mechanical repair and restores the stability of the material structure. It not only overcomes the technical bottleneck of traditional overall heating in achieving uniform temperature control, avoiding the scrapping of the entire blade and significantly reducing maintenance costs, but also features a modular structure and convenient operation, making it suitable for on-site or workshop-level remanufacturing scenarios for aero-engines. It combines technological advancement, economy, and engineering practicality.

[0024] In summary, this invention achieves high-precision and uniform heat treatment of the repair area of ​​complex titanium alloy blades in a vacuum environment through indirect induction heating with contour tooling and root heat replenishment in synergistic temperature control. This effectively eliminates stress, avoids scrapping the entire part, and combines high reliability, economy, and engineering applicability.

[0025] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0027] Figure 1 This is a schematic diagram of the structure of the engine blade vacuum induction heating local repair device provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the engine blade vacuum induction heating local repair device provided in an embodiment of the present invention during operation.

[0029] In the diagram: 1-engine blade, 2-engine blade disk, 3-portable transformer, 4-heating induction heater, 5-contour tooling induction heater, 6-blade contouring heating and insulation tooling, 7-water-cooled cable, 8-cooling water pipe. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only 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. Therefore, they should not be construed as limitations on this invention.

[0032] The following is a detailed description, with reference to the accompanying drawings, of an engine blade vacuum induction heating local repair device and method according to an embodiment of the present invention.

[0033] like Figure 1-2 As shown, an embodiment of the present invention provides a vacuum induction heating local repair device for engine blades, comprising:

[0034] At least two portable transformers 3, each of which includes two water-cooled cables 7 and one cooling water pipe 8, are used to provide high-frequency AC power to the induction heater and achieve effective cooling.

[0035] One set of supplementary heating induction heater 4;

[0036] A set of contour-following induction heaters (5 units);

[0037] A blade contour heating and insulation fixture 6 is made of an oxidation-resistant and high-temperature resistant magnetic metal material. Its internal cavity matches the shape of the aero-engine blade 1 to be repaired, and its exterior is covered with a high-temperature resistant insulation layer. It can be inductively heated and maintained by the contour fixture induction heater 5.

[0038] The contouring tooling induction heater 5 is installed on the blade contouring heating and insulation tooling 6, and the supplementary heating induction heater 4 and the contouring tooling induction heater 5 are respectively electrically connected to the portable transformer 3.

[0039] The engine fan blade assembly to be repaired includes a titanium alloy engine blade 1 and its connected engine blade disk 2.

[0040] The magnetically conductive metal material is selected from molybdenum, nickel, or their alloys (such as mold steel, or other high-temperature resistant and oxidation-resistant alloys may also be used), and can be effectively heated under electromagnetic induction.

[0041] The induction heater 4 is used to perform local electromagnetic induction heating on the area where the root of the engine blade 1 connects to the engine disk 2, in order to compensate for the temperature loss caused by heat conduction, thereby controlling the temperature of the area.

[0042] The high-temperature resistant insulation layer uses ceramic fiber cotton or similar heat insulation materials with a temperature resistance of not less than 1000℃ to reduce heat loss and maintain temperature uniformity.

[0043] Furthermore, the portable transformer 3, the supplementary heating induction heater 4, and the contour tooling induction heater 5 are all modular designs, which can be quickly replaced and combined according to the size and shape of different blade models, thereby improving the versatility and adaptability of the device.

[0044] like Figure 1-2 As shown, one embodiment of the present invention also provides a method for local repair of engine blades using vacuum induction heating, which employs the aforementioned engine blade vacuum induction heating local repair device and includes the following steps:

[0045] The blade-shaped heating and insulation fixture 6 is fixed to the support structure inside the vacuum chamber by positioning pins or slots to ensure its stable position during heating and avoid poor contact with the blade due to vibration or thermal expansion.

[0046] Step 1: Place the regular blade contour heating and heat preservation fixture 6 (heating and heat preservation) in a vacuum environment, and apply an alternating magnetic field to it using the contour fixture induction heater 5. Eddy currents are generated inside the fixture through electromagnetic induction, so that the whole is heated to the set target temperature in the range of 400℃–800℃ and kept at that temperature. Weld multiple thermocouple temperature measuring points on the surface of the engine blade 1 to monitor and control the temperature in real time.

[0047] Specifically, based on the actual shape of the engine blade 1 to be repaired, a blade contour heating and insulation fixture 6 is fabricated using a magnetically conductive, high-temperature resistant, and oxidation-resistant alloy, and its outer surface is wrapped with a high-temperature resistant insulation layer. The contouring fixture induction heater 5 is connected to a high-frequency power system through a portable transformer 3. The contouring fixture induction heater 5 is activated in a vacuum environment to induction heat the blade contour heating and insulation fixture 6, rapidly raising its overall temperature to the set process temperature within the range of 400℃–800℃, and then maintaining it at this temperature to achieve indirect and uniform heating of the titanium alloy blade. At the same time, multiple thermocouples can be spot-welded at key locations on the blade to monitor the temperature in real time and provide feedback for control, ensuring the accuracy of the thermal field.

[0048] Preferably, thermocouple temperature measuring points are arranged in the blade repair area, blade root, and blade disk connection, with a number of no less than 3. The temperature is fed back to the temperature control module in real time through a multi-channel temperature acquisition system to achieve closed-loop control.

[0049] Step 2: Simultaneously start the supplementary heating induction heater 4 (supplementary heating) to locally electromagnetically heat the area where the root of the engine blade 1 connects to the engine blade disk 2, so that the area is maintained at a temperature similar to that of the main body of the engine blade 1. This prevents the engine blade disk 2 from overheating or the root of the engine blade 1 from being too cold due to heat conduction. This achieves precise control and uniformity of the local thermal field of the engine blade 1, avoids thermal stress concentration or deterioration of the material properties of the engine blade disk 2, and prevents the blade 1 and the blade disk 2 from having an excessive temperature difference due to continuous heat transfer.

[0050] Specifically, the induction heater 4 is connected to the power system through another portable transformer 3, and the heater is started synchronously to provide localized heating to the area at the junction of the root of the engine blade 1 and the engine blade disk 2.

[0051] In step one, the heating must be carried out in a vacuum environment to avoid oxidation or gas absorption reactions of the titanium alloy at high temperatures.

[0052] In step one, the target temperature is adjustable within the range of 400℃–800℃, depending on the recrystallization temperature of the titanium alloy material of the engine blade 1 and the requirements of the repair process.

[0053] Through the above two-step coordinated temperature control strategy, this device can achieve precise and uniform heating of local areas of titanium alloy blades in a vacuum environment, effectively eliminating residual stress generated after welding or mechanical damage repair, improving microstructure, restoring mechanical properties, and significantly improving repair quality and service reliability.

[0054] The above embodiments of the present invention provide a vacuum induction heating local repair device and method for engine blades. Through the synergistic temperature control mechanism of the contour-following tooling induction heater 5 and the supplementary heating induction heater 4, it effectively solves the technical problem of uneven temperature control in traditional overall heat treatment of titanium alloy blades due to their complex geometry and uneven thickness. Specifically, it has the following beneficial effects:

[0055] 1) Indirect induction heating is performed using a blade contour heating and insulation fixture 6 made of magnetic metal, and the root heating induction heater 4 is used to dynamically compensate for heat conduction loss, so that the temperature uniformity of each area of ​​the blade is controlled within the set value ±10℃, which significantly improves the consistency of heat treatment.

[0056] 2) Perform precise heat treatment on the repaired titanium alloy blades in a vacuum environment to effectively release the internal stress introduced by welding or mechanical damage repair, restore the stability of the material structure, and ensure service performance.

[0057] 3) It does not require replacing the entire bladed disk assembly; only the damaged blades are repaired and heat-treated locally, which greatly saves expensive titanium alloy materials and precision machining costs, resulting in significant economic benefits.

[0058] 4) It adopts a modular design, including a portable transformer 3, a water cooling system and a dedicated induction coil, which is suitable for on-site or workshop-level aircraft engine maintenance scenarios and has good engineering practicality and promotion value.

[0059] The control, model, and circuit connection of each component are not specifically limited, and can be flexibly configured in practical applications. All circuits, electronic components, and modules involved are existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. Furthermore, the scope of protection of this invention does not involve improvements to the software and methods.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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.

[0061] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A vacuum induction heating local repair device for engine blades, characterized in that, include: At least two portable transformers (3), each of the portable transformers (3) includes two water-cooled cables (7) and one cooling water pipe (8); A set of supplementary heating induction heaters (4); A set of contouring tooling induction heater (5); A blade conformal heating and insulation fixture (6) is made of magnetically conductive metal material. Its internal cavity matches the shape of the aero-engine blade (1) to be repaired, and its exterior is covered with a high-temperature resistant insulation layer. The contouring tooling induction heater (5) is installed on the blade contouring heating and insulation tooling (6), and the heat replenishment induction heater (4) and the contouring tooling induction heater (5) are electrically connected to the portable transformer (3) respectively, so as to achieve heat treatment of the engine blade (1) repair area by indirect induction heating and root heat replenishment in a vacuum environment. The supplementary heating induction heater (4) is used to perform local electromagnetic induction heating on the connection area between the root of the engine blade (1) and the engine blade disk (2); The induction heater (5) of the conformal tooling applies an alternating magnetic field to the blade conformal heating and insulation tooling (6), thereby generating eddy currents inside the tooling to achieve heating.

2. The engine blade vacuum induction heating local repair device according to claim 1, characterized in that, The magnetically conductive metal material is selected from molybdenum, nickel, or their alloys.

3. The engine blade vacuum induction heating local repair device according to claim 1, characterized in that, The high-temperature resistant insulation layer is made of heat-insulating material with a temperature resistance of not less than 1000℃.

4. The engine blade vacuum induction heating local repair device according to claim 3, characterized in that, The heat insulation material is ceramic fiber cotton.

5. The engine blade vacuum induction heating local repair device according to claim 1, characterized in that, The portable transformer (3) consists of two sets, which are electrically connected to the heat replenishment induction heater (4) and the contour tooling induction heater (5) respectively.

6. The engine blade vacuum induction heating local repair device according to claim 1, characterized in that, The target heating temperature range of the blade conformal heating and insulation fixture (6) is 400℃–800℃.

7. The engine blade vacuum induction heating local repair device according to any one of claims 1-6, characterized in that, It also includes thermocouple temperature measuring points, which are welded to the surface of the engine blade (1) for real-time monitoring of the blade temperature.

8. A method for localized repair of engine blades using vacuum induction heating, characterized in that, The engine blade vacuum induction heating local repair device as described in any one of claims 1-7 includes the following steps: Step 1: Place the regular blade contour heating and insulation fixture (6) in a vacuum environment, and apply an alternating magnetic field to it through the contour fixture induction heater (5) to generate eddy currents inside the fixture and heat it to the set target temperature in the range of 400℃–800℃, and keep it warm to achieve indirect heating of the engine blade (1); at the same time, weld thermocouple temperature measuring points on the surface of the engine blade (1) to monitor the temperature in real time and provide feedback for regulation. Step 2: Simultaneously start the supplementary heating induction heater (4) to perform local electromagnetic induction heating on the connection area between the root of the engine blade (1) and the engine blade disk (2), so that the temperature of this area is consistent with the temperature set by the engine blade (1), thereby achieving precise control and uniformity of the local thermal field of the blade.

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