Method for exposing cracks of crowned rotor blade, detection method and casting method

Abstract

The invention belongs to the field of crowned rotor blades of turbine rotors, and particularly relates to a method for exposing cracks of a crowned rotor blade, a detection method and a casting method. The method for exposing the cracks of the crowned rotor blade comprises the steps that the crowned rotor blade is heated to a first preset temperature, and the crowned rotor blade heated to the first preset temperature is cooled to a second preset temperature within preset time; the cracks of the crowned rotor blade are exposed through heating and cooling; a first preset temperature gt; the first preset temperature is smaller than the aging temperature of the material of the crown rotor blade, and the preset time is smaller than or equal to 10 min. According to the method, small invisible micro-cracks located on the shallow surface layer of the crown rotor blade are opened and connected with one another to form linear display cracks; the mode reduces manpower and material resources, shortens the period, and improves the delivery efficiency of the engine; meanwhile, cracks are displayed, so that detection is facilitated, and detection accuracy and detection efficiency are improved; and it is ensured that the installed crown rotor blade is free of cracks and micro cracks.

Description

Technical Field

[0001] The invention belongs to the field of turbine rotor crowned rotor blades, and in particular relates to a method for exposing cracks in crowned rotor blades, a detection method and a casting method. Background Art

[0002] The aircraft engine is an important part of the aircraft, and the performance of the aircraft engine affects the flight safety of the aircraft. The aircraft engine includes a turbine, and the shrouded rotor blades are an important part of the turbine. In order to ensure the performance of the aircraft engine, it is necessary to ensure that there are no cracks on the installed shrouded rotor blades. If the shrouded rotor blades with invisible microcracks are installed, the service life of the aircraft engine will be shortened and the danger of using the aircraft engine will be increased. Therefore, before the shrouded rotor blades are installed, it is necessary to ensure that there are no cracks.

[0003] During the casting process of the crowned rotor blades, Figure 1 As shown, casting thermal cracks are easily formed at the blade intake and exhaust edges and the crown transition R; existing detection methods include X-ray detection method and fluorescence detection method, but when the casting thermal cracks are not exposed or the opening is small, hidden micro cracks are formed, which are difficult to detect using fluorescence, X-ray detection and fluorescence detection, resulting in low detection accuracy.

[0004] In order to detect hidden microcracks on crowned rotor blades and improve the service life and safety of aircraft engines, before installation, the engine can be installed and tested twice to detect blades with casting thermal cracks. That is, the crowned rotor blades are installed on the engine and a factory test is carried out. After the test, the engine is disassembled and inspected. After passing the inspection, it is reassembled and tested in the factory. The above measures are taken to expose the invisible microcracks, and the exposed invisible microcracks can be detected. However, this method requires a lot of manpower, material resources and time, which is not conducive to the rapid delivery of the engine.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a method for exposing cracks in crowned rotor blades, a detection method and a casting method. Under the combined action of heating and cooling, the crowned rotor blades of the present invention cause the tiny invisible microcracks located on the shallow surface of the crowned rotor blades to open and connect with each other to form linear display cracks; this method reduces manpower, material resources and cycles, and improves the delivery efficiency of the engine; at the same time, display cracks are more conducive to detection, thereby improving detection accuracy and detection efficiency; and ensuring that the installed crowned rotor blades are free of cracks and microcracks.

[0007] The present invention includes the following technical solutions:

[0008] A first aspect of the present invention provides a method for exposing cracks in a shrouded rotor blade, wherein the shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; the cracks in the shrouded rotor blade are exposed by heating and cooling;

[0009] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0010] Furthermore, the heating is performed in a vacuum furnace.

[0011] Furthermore, the crowned rotor blades are heated to a first preset temperature and then kept warm for ≥10 minutes before being cooled.

[0012] Furthermore, the second preset temperature is ≤80°C.

[0013] A second aspect of the present invention provides a method for detecting cracks in a crowned rotor blade, the method comprising the following steps:

[0014] The cast crowned rotor blade is heated to a first preset temperature, and the crowned rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks of the crowned rotor blade are exposed by heating and cooling;

[0015] Detect cracks in crowned rotor blades by fluorescence detection method;

[0016] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0017] A third aspect of the present invention provides a casting method for exposing cracks in a crowned rotor blade, the casting method comprising the following steps:

[0018] The crowned rotor blades are obtained through wax model preparation, shell preparation, melting and pouring, and vacuum heat treatment;

[0019] The shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks in the shrouded rotor blade are exposed by heating and cooling;

[0020] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0021] Furthermore, the casting method comprises the following steps:

[0022] The crowned rotor blades are obtained through wax model preparation, shell preparation, melting and pouring, and vacuum heat treatment;

[0023] The shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks in the shrouded rotor blade are exposed by heating and cooling;

[0024] Detect cracks in the crowned rotor blades by a fluorescence detection method to obtain a crowned rotor blade without cracks;

[0025] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0026] Furthermore, after heating the crowned rotor blades to a first preset temperature, the crowned rotor blades heated to the first preset temperature are cooled to a second preset temperature within a preset time; and before the cracks of the crowned rotor blades are exposed by heating and cooling, X-ray detection is performed first.

[0027] Furthermore, before the X-ray inspection, the crowned rotor blades are subjected to low-magnification corrosion, grain size inspection and surface finishing.

[0028] Furthermore, before detecting cracks in the shrouded rotor blades by a fluorescence detection method to obtain shrouded rotor blades without cracks, the shrouded rotor blades are pickled.

[0029] By adopting the above technical solution, the present invention has the following advantages:

[0030] 1. Under the combined effects of heating and cooling, the crowned rotor blades of the present invention cause the tiny invisible microcracks located on the shallow surface of the crowned rotor blades to open and connect to each other, forming linear visible cracks; this method reduces manpower, material resources and cycles, and improves the delivery efficiency of the engine; at the same time, the visible cracks are more conducive to detection, improving the detection accuracy and efficiency; and ensuring that the installed crowned rotor blades are free of cracks and microcracks.

[0031] 2. The method of the present invention accelerates the exposure of casting thermal cracks of crowned rotor blades and uses a non-destructive method to detect problematic crowned rotor blades, which has the advantages of saving time and labor, high reliability, and greatly improving the delivery efficiency of aircraft engines.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 Schematic diagram of crack display of a crowned rotor blade in an embodiment of the present invention;

[0035] Figure 2 The present invention is a flowchart of a method for exposing cracks in a shrouded rotor blade according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] This embodiment provides a method for exposing cracks in a shrouded rotor blade, such as Figure 2 As shown, the shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; the cracks of the shrouded rotor blade are exposed by heating and cooling;

[0039] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0040] The method for exposing cracks on a crowned rotor blade of the present invention can quickly expose microcracks on a crowned rotor blade, and has the advantages of improving the accuracy and efficiency of crack detection.

[0041] During the heating and cooling process of the crowned rotor blades, there is a certain temperature gradient at each position of the blades, which will generate certain thermal stress, promoting the gradual opening and interconnection of the tiny invisible microcracks inside the blades, forming linear visible cracks that can be detected by fluorescent inspection. Moreover, this process has the same effect as the thermal shock of the blades during the engine start-up and shutdown process, and will not affect the use of the crowned rotor blades.

[0042] Since the crowned rotor blades are made of metal material, there is a possibility of oxidation of the crowned rotor blades when directly heated in the atmospheric environment. In order to prevent oxidation and improve detection efficiency, further, in some embodiments, the heating is performed in a vacuum furnace.

[0043] Furthermore, in some embodiments, the crowned rotor blade is heated to a first preset temperature and then kept warm for ≥10 minutes before being cooled. After being kept warm for ≥10 minutes, the blade is fully heated and the overall temperature reaches the aging temperature of the blade. At this time, the thermal stress of the blade reaches the maximum. After the thermal stress of the blade is released, the micro cracks of the blade can be fully expanded and fully exposed; specifically, the advantage of further improving the accuracy of crack detection.

[0044] Furthermore, in some embodiments, the second preset temperature is ≤80° C. This temperature can cooperate with the first preset temperature to produce a rapid and sharp cooling process, so that the thermal stress inside the blade is released, and the microcracks inside the blade are promoted to continuously expand and expose to become linear display cracks; at the same time, this temperature also facilitates the removal of the crowned rotor blade from the vacuum furnace.

[0045] This embodiment also provides a method for detecting cracks in a crowned rotor blade, the method comprising the following steps:

[0046] The cast crowned rotor blade is heated to a first preset temperature, and the crowned rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks of the crowned rotor blade are exposed by heating and cooling;

[0047] Detect cracks in crowned rotor blades by fluorescence detection method;

[0048] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0049] The detection method of the present invention has the advantages of high detection efficiency and high detection accuracy.

[0050] This embodiment also provides a casting method for exposing cracks in shrouded rotor blades, the casting method comprising the following steps:

[0051] The crowned rotor blades are obtained through wax model preparation, shell preparation, melting and pouring, and vacuum heat treatment;

[0052] The shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks in the shrouded rotor blade are exposed by heating and cooling;

[0053] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0054] The casting method of the present invention can expose micro cracks in the shrouded rotor blades, so that the cracks can be detected, thereby improving the qualified rate of the shrouded rotor blade casting.

[0055] This embodiment also provides a method for casting a crowned rotor, the method comprising the following steps: preparing a wax mold, preparing a shell, melting and pouring, and performing vacuum heat treatment to obtain a crowned rotor blade;

[0056] The shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks in the shrouded rotor blade are exposed by heating and cooling;

[0057] Detect cracks in the crowned rotor blades by a fluorescence detection method to obtain a crowned rotor blade without cracks;

[0058] Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

[0059] The crowned rotor obtained by the casting method of the present invention has a high pass rate and has the advantage of improving the performance and safety of the aircraft engine after installation.

[0060] Further, in some embodiments, after heating the shrouded rotor blade to a first preset temperature, cooling the shrouded rotor blade heated to the first preset temperature to a second preset temperature within a preset time; and before exposing the cracks of the shrouded rotor blade by heating and cooling, an X-ray inspection is first performed. The shrouded rotor with cracks is first detected, thus reducing the process of heating and cooling to expose microcracks, which has the advantage of reducing costs.

[0061] Furthermore, in some embodiments, before the X-ray inspection, the crowned rotor blades are subjected to low-magnification etching, grain size inspection and surface finishing. Low-magnification etching facilitates the blades to be subjected to grain size inspection, and surface finishing can be used to modify the blades to meet the requirements of the external dimensions.

[0062] In order to further improve the accuracy of crack detection, further, in some embodiments, before detecting cracks in the shrouded rotor blades by a fluorescence detection method to obtain shrouded rotor blades without cracks, the shrouded rotor blades are pickled.

[0063] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0064] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for exposing cracks in a shrouded rotor blade, It is characterized in that The shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks in the shrouded rotor blade are exposed by heating and cooling; Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

2. A method for exposing cracks in a shrouded rotor blade according to claim 1, It is characterized in that The heating is carried out in a vacuum furnace.

3. A method for exposing cracks in a shrouded rotor blade according to claim 1 or 2, It is characterized in that The crowned rotor blades are heated to a first preset temperature and kept at that temperature for ≥10 minutes before being cooled down.

4. A method for exposing cracks in a shrouded rotor blade according to claim 3, It is characterized in that The second preset temperature is ≤80°C.

5. A method for detecting cracks in crowned rotor blades, It is characterized in that The detection method comprises the following steps: The cast crowned rotor blade is heated to a first preset temperature, and the crowned rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks of the crowned rotor blade are exposed by heating and cooling; Detect cracks in crowned rotor blades by fluorescence detection method; Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

6. A casting method for exposing cracks in crowned rotor blades, It is characterized in that The casting method comprises the following steps: A crowned rotor blade is obtained through wax mold preparation, shell preparation, melting and pouring, and vacuum heat treatment; the crowned rotor blade is heated to a first preset temperature, and the crowned rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks of the crowned rotor blade are exposed by heating and cooling; Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

7. A method for casting a crowned rotor, It is characterized in that The casting method comprises the following steps: The crowned rotor blades are obtained through wax model preparation, shell preparation, melting and pouring, and vacuum heat treatment; The shrouded rotor blade is heated to a first preset temperature, and the shrouded rotor blade heated to the first preset temperature is cooled to a second preset temperature within a preset time; cracks in the shrouded rotor blade are exposed by heating and cooling; Detect cracks in the crowned rotor blades by a fluorescence detection method to obtain a crowned rotor blade without cracks; Wherein: the first preset temperature>the second preset temperature, the first preset temperature is lower than the aging temperature of the material of the crowned rotor blade, and the preset time is ≤10min.

8. A method for casting a crowned rotor according to claim 7, It is characterized in that The crowned rotor blades are heated to a first preset temperature and cooled to a second preset temperature within a preset time; and before cracks of the crowned rotor blades are exposed by heating and cooling, an X-ray inspection is performed.

9. A method for casting a crowned rotor according to claim 8, It is characterized in that Prior to X-ray inspection, the crowned rotor blades are subjected to low-magnification erosion, grain size inspection and surface finishing.

10. A method for casting a crowned rotor according to claim 7 or 8, It is characterized in that Before detecting cracks in the shrouded rotor blades by a fluorescence detection method to obtain shrouded rotor blades without cracks, the shrouded rotor blades are pickled.

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